bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on the Global Stability of the xiaowan Arch Dam Using a 3D Geo-mechanical Model Test
Authors: Dong Jianhua , Wang Xianlian , Chen Jianye , Chen Yuan , Yang Baoquan , Zhang Lin
Published: September 2019

In this paper, a three-dimensional geo-mechanical model test for the Xiaowan high arch dam was studied and the topographical and geological features, the distribution of weak structural planes, the shallow relaxation unloading phenomena were simulated. Furthermore, a type of model material known as the temperature analogous material, whose strength varies with temperature throughout the experiment, was used to simulate the decrease in shear strength of the weak structural planes. The deformation characteristics and failure mechanism of the dam foundation and abutments were obtained by using comprehensive test method, which considered both the overloading and strength-reduction techniques. Through data analysis, the strength reserve coefficient, the overloading and the global safety factor were obtained. Synthetic analysis of the test results indicates that the displacement of the mid-upper abutment was reduced and the failure zone become smaller due to the significant reinforcement effects of concrete displacement plugs on the faults and alteration zones. The failure pattern shown in the model test indicates that reinforcements should be installed at faults F11 and F10 above an elevation of 1245 m in the right abutment and the rock above the thrust block in the left abutment.
Analysis on Implementation Effect of Groundwater Over-exploitation Comprehensive Control Water Conservancy Project—Taking Linzhang County as an Example
Authors: Wang Danyang , Zhang Jing , Zhao Jinyong , Fu Yicheng , Zhao Xinkai , Gong Shaopeng
Published: September 2019

In order to effectively solve the problem of over-exploitation of groundwater in Hebei Province and achieve the balance of groundwater recovery, Hebei Province began to conduct pilot research on comprehensive management of groundwater over-exploitation in 2014. Taking Linyi County in the south of Hebei Province as an example, this paper studies the effect of pressure extraction on groundwater over-exploitation comprehensive treatment of water conservancy projects in 2015, analyzes and summarizes the experience, deficiencies and improvement measures of groundwater pressure mining work, in order to follow the groundwater pressure mining work. Provide guidance for reference. The results show that: Linyi County’s 2015 water conservancy project achieved a pressure recovery capacity of 4.02 million m3, and the water-saving pressure mining effect was remarkable. Among them, the sprinkler irrigation water-saving facilities have an average water saving capacity of 105 m3/mu, and the water-saving efficiency is obvious. In addition, the next stage of work should pay attention to the study of water-saving measures based on water-saving management and regional agriculture represented by crop planting structure adjustment. Irrigation pattern, implementation of field engineering work, to form a regional scale, intensive water-saving irrigation pattern, promote the promotion and application of groundwater over-exploitation comprehensive treatment in Hebei Province.
Explore on the Dynamic Cause of Local Scouring
Authors: Liu Meng , Zhang Hong-wei
Published: September 2019

Based on the physical model test method, the dynamic cause of local scouring is explored. Result shows that uneven distribution of vertical turbulence intensity of near-bottom flow is the main driving force for local scouring. Distribution characteristics of vertical turbulence intensity of the near-bottom flow determine the spatial shape of the local scouring, that is, the range and the extreme-deep point of the local scouring correspond to the position of the strong turbulent zone and maximum value respectively. When the effect of the near-bottom strong turbulence zone on the riverbed is completely isolated, local scouring disappears, otherwise it will occur in the uninsulated part.
An Extensive Analysis of Oscillations in Arbitrary Harbors with Reflecting, Absorbing and Transmitting Boundaries – Case study of the Port of Indiana
Authors: Chang YanSheng , Wu JiunYuen
Published: September 2019

The harbor resonance numerical model can be applied to wave response in the harbor, groups of linear and nonlinear waves with high crest pose hazards to ships, inducing harbor resonance and over-topping of structures. The model, a two-dimensional linear, inviscid, dispersive, hybrid finite element to simulate harbor resonance with conservation of energy approach, is applicable in an offshore or coastal harbor of arbitrary shape. The model incorporates the effects of variable bathymetry, bottom friction, variable, full or partial absorbing boundaries as well as wave transmission through permeable breakwaters. The accuracy and efficiency of the present model will be verified by comparing with those of experimental and field data of the Port of Indiana, where wave incidences of ship damage, broken mooring lines and barge sinking, particularly in the grain dock area. It is important to study the behavior of incident wave periods and the associated maximum harbor resonant response at key points within the harbor. The model results were proved to be consistent with observations which lead to the conclusion that the model is well suited for use in harbors of irregular geometry with transmissivity boundaries. The model presented herein is a realistic method for solving arbitrary harbor resonance problems.
Construction Technology of Pipe Pile in the Reclamation Project
Authors: Xu ZhiXiong
Published: September 2019

Combining the successful experience on the formation of same kind, bore-making technique in the pipe pile construction of reclamation project and its solution are put forward, such as the selection of construction machines, construction technology, which provides reference for the project of the same kind.
Minimum Potential Energy Principle on Slip Calculation of Composite Beams
Authors: Chen Xu , Xiong Pingjia , Ma Jianghong
Published: September 2019

Energy method has the mathimatical convenience because it is scalar. The work potential is work done by external forces. After it is transfered to the work done by the internal force, the classical second-order differential equation of slip effects is deduced according to Minimum Potential Energy Principal. In the derivation, integration by parts is used to transfer the higher order variation into the first order according to Euler Equation. For simply-supported composite beam, the slip-induced stresses are self-equilibrium and the redistributed internal forces are significant. The slip effects is important for composite beams in service time, like the compresion stress of the top flange of steel beam may become the 11.5 times, which arises the problem of local buckling.
Discussion on Abnormal Values in Static Penetration Data
Authors: Xue-xiang Liu , Dao-xiang Wu
Published: September 2019

As the mainstream method of in-situ testing technology, static penetration testing is widely used. At present, the implementation of a large number of projects must be based on its test results. It also makes us have to pay attention to the reliability of its test results. In this paper, based on the previous experience and combined with the static penetration data in Hefei area, the reliability of test data is studied. The abnormal data in the static penetration data is eliminated and the influence of the abnormal data on the calculation results of correlation distance is expounded.
Analysis on the Defense Safety Design of Non-gated Residential Building’s Outside Environment in Changchun in the Perspective of Reducing Spatial Blind Zones: A Case study of Sanfujie Community
Authors: Wang Keqi , Chen Xiaodong , Liu Lu
Published: September 2019

Rapid urbanization in China brings about many spatial blind zones (abbr. SBZs), which are kinds of undesirable spaces that stimulate urban crime. The SBZ is divided into three categories, which are the position-based SBZ, the morphology-based SBZ and the atmosphere-based SBZ. The physical elements that cause the SBZ mainly contain three aspects, the building factors, the landscape factors and the traffic factors. After analyzing how the SBZ impacts on the defense safety, the author proposes the series of thoughts on how to cut down SBZs based on CPTED theories. Meanwhile, the author analyzes the defense safety problems about position, morphology and atmosphere caused by improper design of buildings, landscape and traffic factors in Sanfujie, a typical non-gated residential community, and puts forward corresponding improvement strategies.
Stochastic Finite-Fault Method Based on Dynamic Corner Frequency to Simulate the Mw6.2 Tottori earthquake in Japan
Authors: Xia Songlin , Liu Qifang , Song Jian
Published: September 2019

Stochastic finite-fault method is the main method to simulate near field strong earthquakes in current seismic engineering. For specific ground motion, the accuracy of parameter selection is important, such as field effect, because the number of rock sites is scarce in many areas of China, the calculation of crustal amplification and site amplification of a specific soft soil site can not only eliminate the limitation of station selection, but also improve the accuracy of simulation results. In this paper, a stochastic finite-fault method based on dynamic corner frequency is used to simulate the Mw6.2 Tottori earthquake on October 21, 2016 in Japan. The comparison with the actual records shows that the simulation results are in good agreement with the short period and have great feasibility. This paper discusses the differences between the simulated response spectra (PSA) of stations with various azimuths and the observed one. Meanwhile, it also demonstrates the dissimilarities in simulation results between the stations located on the hanging wall and those located on the flat wall of the fault plane. The results show that for soft soil sites, crustal amplification and site amplification, as well as the geometrical position relationship between stations and faults have a certain impact on the simulation results. Based on the calculation of specific crustal amplification and site amplification in a specific region, the location relationship between stations and faults is included in the analysis, so that the future earthquake can be predicted more accurately, and an important reference can be provided for the disaster assessment in this region and the site selection of major projects.
The effect of duration of strong ground motion on the ductility demand of SDOF structure
Authors: Lingfeng Kong , Maosheng Gong , Zhanxuan Zuo
Published: September 2019

As one of the basic parameters of strong ground motion, the duration of strong ground motion has not been considered in the seismic design codes over the world. To study the ground motion duration on the effects of the SDOF structure ductility demand, the Ds5-75 is chosen as the duration index, and the ductility demand ratio spectrum under long and short ground motion is calculated, then the effect of duration on structural ductility demand under different strength reduction factor is analyzed. The results show that the ductility demand of the structure under long duration ground motion is significantly greater than that under the short duration ground motion. For most periods, the ductility demand of long-duration ground motion is 1.3 times that of short-duration ground motion, and the maximum is 2.5 times. It is suggested that the effect of duration should be considered when the time history analysis of structure is carried out.
A New Water Leakage Classification Method for Tunnel Lining Based on Traffic Safety
Authors: Ding Hao , Jiang Xinghong , Li Ke , Hu Xuebing , Cheng Liang
Published: September 2019

Leakage disease would adversely affect the lining structure and operation environment, which may endanger the normal operation of tunnel projects. Existing leakage classification standards for tunnels are mainly based on the apparent view state, and the impacts of the actual operating environment are not fully taken into consideration. Based on the current classification standards, guidelines and the shortcomings of the current classification system, a new method has been put forward to classify the leakage of tunnel lining considering the influence on driving safety. In addition, Numerical software (CARSIM) is used to investigate the safety states of passenger car and freight car in different leakage level, vehicle types and driving speed conditions. Simulation results show that the maximal speed of passenger car on the road surface with a leakage-water depth of 1 mm, 5 mm and 11 mm is 110 km/h, 95 km/h and 75 km/h respectively; while that of freight car is 90 km/h, 85 km/h, and 60 km/h respectively in the same condition. The results of overtaking simulation on the two-shift line surface with 5-mm-deep leakage indicate that cars will not be unstable as the speed increases. However, when the speed of passenger car exceeds a critical value, a large error between actual trajectory and the expected dual-trajectory would appear. It would easily cause lane departure and vehicle collision. When the speed of freight car exceeds a critical value on the double-shift line, the yaw rate, side slip angle, lateral acceleration and lateral displacement velocity would go out of control. Combining with the tunnel leakage states and driving operation, this paper establishes a new classification method of tunnel leakage disease based on operation safety. It makes up for the insufficiency of tunnel leakage classification method and has guiding significance in actual tunnel projects.
A Capillarity-dependent Model for Prediction of Chloride Penetration Process into Concrete in Artificial Splash Test
Authors: Han Xun , Guan Yunfei , Cao Yongyong , Zhang Jianyi
Published: September 2019

In order to better simulate the penetration process of chloride ions in the splash zone of concrete, this paper modified existing chloride ion transport model on the basis of capillarity-dependent model under unsaturated and non-pressure conditions to make it applicable to the calcualtion of choride flow flux. The artificial splash tests is firstly designed and conducted under varied conditions of water to cement ratio, splash time duratinoa and splash period. Then the original chloride constitutive model is improved by enhancement of convection term calculation. At last, the authors simulate the chloride ions penetration process under different conditions by reasonble design of equivalent chloride and moisture boundary to verify the effectiveness of capillarity-dependent model.
Micro-analysis of Marine Sand From Zhoushan Seas
Authors: Di WU , Yan Qian , Wang Ya-jun , Gan Xiao-qing , Dong Zhi-hong , Wang Jin-bao , Chen Jing-jin
Published: September 2019

The main salt components and ion content of seawater were qualitatively and quantitatively analyzed. The results show that the seawater in this region has low ion content and low salt content, and direct application is relatively beneficial to engineering. Meantime, the property test was carried out to investigate the basic physical behavior of the goal sea sand. The results show that Zhoushan sea sand has low chloride ion content, uniform particle size and Low mud content.
Pricing and Incentive Strategy for Green Building Supply Chain with Incentive Mechanism
Authors: Jiang Wen , Huang Xiaoyan , Zhou Ying
Published: September 2019

We are witnessing more frequent extreme weather events due to the global warming. Construction industry has a high carbon footprint, the development of green building is a necessary way to protect the environment and achieve sustainable development of construction Industry. The government has formulated a series of financial subsidies policies and tax preferential policies to promote the development of green buildings. Contractors play an important role in the construction process, but there is no incentive mechanism to encourage contractors to work hard to improve the green building level. This paper studies the incentive mechanism and pricing strategy of green building under a two-level supply chain system consisting of a developer and a contractor. The optimal incentive intensity and optimal price of the developer, and optimal green level of the contractor is obtained. The results show that the incentive mechanism can not only increase the profits of the developer and the contractor but also improve the green building level, then promote the sustainable development of the construction industry.
Assessment of Seismic Fragility of RC Fram Based on Different Methods for Selecting Index Threshold
Authors: Jitao Yao , Jun Gao , Liuzhuo Chen
Published: September 2019

In the current structure damage assessment process, different methods of selecting damage index threshold will significantly affect assessment results. OpenSees finite element software is used to build a 6-story RC frame structure model. Then, the inter-story drift and residual inter-story drift are used as single and double indices to calculate threshold values using the code method and the incremental dynamic analysis method. Evaluation results vary more significantly when the damage is evaluated using a single index. When the threshold is selected based using the code method with a double index, the results are more conservative. The stronger the correlation between the inter-story drift and residual inter-story drift is, the more conservative the results are.
Experimental Study on At-rest Lateral Earth Pressure Coefficient of Cemented Clay
Authors: Wu Zhiqiang , Cai Zhengyin , Xu Kai , Guan Yunfei , Huang Yinghao , Geng Zhizhou
Published: September 2019

The determination of lateral earth pressure is of practical importance and plays an important role in the design of retaining structures. Test results of at-rest lateral stress, coefficient of earth pressure at rest and its change law of an artificially cemented clay were presented in this paper. A K
0 consolidometer was utilized to measure the at-rest lateral stress and vertical compression of the specimen. The test material was a Lianyungang marine clay and was mixed with a special kind of Portland cement that was designed for ocean engineering. The cement contents were 4, 6, 8, 10 and 12% by weight of dry soil particles and the curing time was 7, 14, 28, 60 and 90 days. The test results indicate that the at-rest lateral stress of cemented clay is different from that of uncemented clay. And at-rest lateral stress decreases rapidly with an increase in cement content and curing time. However, the lateral stress increases sharply when the applied load exceeds the vertical yield stress, which causes a corresponding change in K0.
The application of artificial immune algorithm to earthquake relief route planning
Authors: Liu Lifeng , Wang Zhiyong
Published: September 2019

After an extreme earthquake attacks an urban area with many mountains, the main objective of a search and rescue operation is to minimize the number of fatalities. Therefore the task of transportation rescue resources to operational areas is of great importance to disaster managers. This paper presents a quick path planning method based on Artificial Immune Algorithm (AIA) and helicopter operation performance in order to design an optimal path for an operational area. First, a simulation of an earthquake is implemented in environment only including terrain threat. Second, a more complex model contains terrain, weather, building and communication threats simulation is executed and the resulting performance measures are evaluated by considering the survival time and total value for taken out entrapped occupants in the disaster area. Additionally, the best parameters of planning path for dual helicopters to an operational area are determined. Further work will be dedicated to adding real 3D terrain model into the current threat model.
An Experimental Study on the Behavior Deterioration Trend of Friction Pendulum Bearings with Corrosion Time for Offshore Isolated Bridges
Authors: Zhao Guifeng , Ma Yuhong , Li Yanmin , Su Liangjian , Zhou Fulin
Published: September 2019

At present, the behavior deterioration trend of friction pendulum bearings (FPBs) widely used in offshore bridges under marine environment isn’t still clear. In this study, periodic-salt-spray and wetting–drying cycle accelerated corrosion tests were used to simulate the corrosion circumstances of FPBs in the splash and atmospheric zones, respectively. Eight sets of FPBs with a vertical bearing capacity of 35 t were designed as test samples. The environmental factors that affect the bearing behavior deterioration were analyzed; the test accelerated ratios of the factors were discussed; two kinds of test schemes were designed for the FPBs; and the macroscopic appearances of the FPBs at different corrosion times were observed. The trends of the initial static and dynamic friction coefficients with corrosion time were extensively analyzed, and the behavior deterioration trends of the mechanical properties of the FPBs were analyzed. The results show that in both the splash and atmospheric zones, the initial static and dynamic friction coefficients with corrosion time show an increasing periodic curve, but the behavior deterioration trend and period of FPBs in different locations are different. The vertical and horizontal stiffness of FPBs almost did not change with the corrosion time. The trends of equivalent damping ratio with the corrosion time are consistent with the dynamic friction coefficient. Based on the experimental results, the behavior deterioration trends of the initial static and dynamic friction coefficients of FPBs with corrosion time were obtained, which provides a basis for the seismic performance evaluations of offshore isolated bridges in their entire service lifetime.
Seismic dynamic response analysis of permeable breakwater on piled foundation considering pile-soil interaction
Authors: Zhang Duohan , Gui Jinsong
Published: September 2019

In order to discuss the seismic response of pile foundation permeable breakwater structure under different working conditions, the dynamic implicit module in finite element software ABAQUS is used to analyze the seismic dynamic response of pile foundation permeable breakwater. Considering the nonlinear characteristics of pile-soil interaction the breakwater is simulated under different seismic intensity conditions. The acceleration, bending moment of pile foundation are analyzed by time-history analysis method. The influence of pile diameter on the whole structure is compared. The results show that the stronger the earthquake is, the more obvious the overall dynamic response of the structure is. The bending moment of pile body decreases first and then increases. The wider the diameter of pile foundation, the greater the stiffness of the whole structure, resulting in an increase in the seismic force received by the structure. Compared with the static load, the influence of earthquake on the permeable pile breakwater can not be ignored.
Seismic dynamic stability analysis of landslide based on unbalanced thrust method
Authors: Mei Hongru , Luo Hongxing , Sheng Qian , Chen He , Zhang Zhenping , Fu Xiaodong , Zhao Xin
Published: September 2019

The unbalanced thrust method is one of the main research methods for the stability evaluation of the geological hazard of the landslide caused by the earthquake. When the traditional unbalanced thrust method is used to calculate the safety factor of the seismic downhill slope, all the soil strips use the same seismic acceleration. This treatment does not consider the propagation process of seismic waves in the landslide body. In this paper, the peak acceleration of the seismic center of each soil strip is obtained by numerical simulation, considering the temporal and spatial variation of seismic waves in soil strip, forming an imbalance considering multi-point seismic action thrust method. Based on this, taking the landslide formed by the K92 roadbed excavation of a highway in Yunnan as an example, the unbalanced thrust and safety factor under different seismic intensities are analyzed, and the engineering reinforcement effect is studied. Analysis shows that: sliding surface has obvious sliding section and anti-slip section, and the sliding section is distributed in the soil block with large inclination angle at the trailing edge of the landslide,and the anti-slip section is distributed in the lower part of the landslide; the landslide is in an unstable state after excavation, which is consistent with the scene.After comprehensive measures such as slope reduction, anti-slide pile reinforcement and prestressed anchor cable reinforcement, the landslide meets the requirements of earthquake resistance against IX. The research results provide an effective method for the evaluation of dynamic stability of landslides caused by earthquakes.
Probability analysis of setback distance based on structural damage near earthquake-fault-rupture
Authors: Zhang Jianyi , Bo Jingshan , Li Ping , Shen Chao
Published: September 2019

The probabilistic analysis method is the inevitable result of the development of engineering seismic science and adapts to the current level of people’s understanding. This paper systematically summarizes the seismic damage of the engineering structures near the surface rupture zone of strong earthquakes in Yushu earthquake, Wenchuan earthquake and Jiji earthquake in recent years. According to the quantitative relationship between building damage index and distance, probability analysis results of the setback distance is given. This result is easy to popularize and apply, and lays a foundation for probabilistic risk analysis of buildings close to the surface rupture zone of strong earthquakes.
Discussion on Safety Early Warning Management in Building Construction
Authors: Li Kui
Published: September 2019

With the continuous development of social economy and the improvement of people’s living standards, the construction industry has been further developed. People attach great importance to the quality of construction. In construction, safety accidents threaten the safety of construction personnel, affect the stability of construction, and definitely affect the quality of later projects. In order to ensure the sustainable development of construction projects, it is necessary to establish and improve the safety early warning system, reduce the occurrence of safety accidents, and promote the sustainable development of construction enterprises. Following is a detailed analysis of the safety early warning management in building construction, in order to provide effective reference for promoting the sustainable development of the construction industry.
Study on Stability of Super-high Straight-web Cellular Steel Sheet Pile Cofferdam
Authors: Deng Yang , He Changhai , Fu Shaojun , Wu Xiguo , Yang Ruiting
Published: September 2019

In recent years, steel sheet pile cofferdam has been adopted in some hydropower reconstruction and extension projects because of its many advantages. However, due to insufficient understanding of the bearing mechanism of super-high cellular cofferdam and lack of Engineering experience, there is no exact method to accurately predict the deformation and failure forms of the cofferdam, and there is no perfect safety and economic design theory, which restricts its popularization and application. Taking the Tarbela 4th Extension Project as background, the mechanical behavior and stability evaluation of the cofferdam in 30m deep water during construction and operation are studied by FEM, and influence of structural form and parameters on deformation characteristics of key parts is analysed. Results show that the maximum interlock tension occurs near mudline or top of berm during high lateral load. Development distribution of shear deformation are more in line with the Kitajima Shoichi’ method. The overturning deformation of cell can be effectively restrained by embedment, the rotation point changes regularly with the increase of berm and embedment. The sliding surface in cell conforms to Hansen’s calculation theory, the position of rotation and change of base pressure are closer to the Japanese standard. With the stiffness loss, the change of interlock tension is similar to the damage of low carbon steel, the shear sliding surface is related to berm which above the top overturning deformation is the largest. Based on the stability of cofferdam, there are various combinations of berm height and embedded depth, which can reduce the quantity of embankment works and the cost of later maintenance. The research results are of reference significance for the design and construction of similar super-high steel sheet pile cofferdams.
Reconstruction and Reinforcement New Techniques for Masonry Gravity Dams Upstream Anti-seepage Panels
Authors: Qi Peng , Dashui Gao
Published: September 2019

Masonry gravity dam type has been used widely in developing countries, in which China also has built many masonry gravity dams in the past. most of the masonry gravity dams have the structure of internal masonry and external reinforced concrete. Due to much internal masonry void, the dam upstream anti-seepage panel becomes the key part of its dam body anti-seepage system. After a long-time running, many masonry gravity dams’ upstream concrete panels have appeared many deficiencies such as aging, cracking, exposing steel bars and separating calcium, which have generated serious leakage problems, and then threatened the safety of the dams’ body and residents downstream, consequently the upstream anti-seepage panels should be restructured and reinforced with new techniques. This article summarizes technical difficulties and methods of masonry gravity dams’ upstream anti-seepage panels reconstruction and reinforcement, it also combined with an engineering project to introduce the new techniques and its effect of the upstream anti-seepage panel reconstruction and reinforcement.
Experimental Study on Bond Properties between FRP Bars and Coral Concrete
Authors: Chen Shuang , LÜ Haibo
Published: September 2019

The bonding behavior between Fiber Reinforced Plastic (FRP) bars and concrete is the most basic mechanical behavior of FRP-reinforced concrete structural, which affects the structural calculation and performance analysis. However, few studies involved coral concrete. The experimental study on the bond behavior between FRP bars and coral concrete was carried out. The results showed that the bond strength of FRP and coral concrete can meet the general engineering needs.
Analysis of Seismic Behavior of Four-side Partially Connected Steel Plate Shear Wall
Authors: Dong Lu , Yin Fuxin
Published: September 2019

Four-side partially connected steel plate shear wall is the structure that frame and plate are incompletely connected. Through the analysis of mechanism, it shows that, when compared with traditional completely connected steel plate shear wall, the partially connected one causes less additional bending moment on frame. In order to further learn about the behavior of partially connected steel plate shear wall, this paper used FE modeling method on ABAQUS. The paper analyzed the influences of the frame-plate connection ratio and the height-thickness ratio of steel plate on the behavior of unstiffened four-side partially connected steel plate shear wall, and investigated the function of three different forms of stiffeners on partially connected steel plate shear wall.
Post-peak roughness degradation model based on Barton-Bandis criterion for rock joint
Authors: Wang Jinmei , Zhang Yingbin , Wang Pan
Published: September 2019

Based on the non-linear shear behaviour obtained by many researchers’ direct shear test, an exponential degradation model about the joint roughness is introduced into Barton-Bandis shear strength criterion to describe the non-linear post-peak shear behaviour. In the degradation model, the joint roughness coefficient (JRC) gradually decreases with the shear displacement to account for asperity degradation during shear process, and the decay rate decreases. Finally the JRC falls to a constant value that corresponds to the residual shear resistance of the joint and the decay rate decreases to zero. At last, the model is used to fit experimental data for different materials of joints, and the high fitting accuracy shows its validity.
Reliability Assessment on Stability of Slopes Reinforced with Anti-sliding Piles in Spatially Variable Soils
Authors: Yang Changyou , Cheng Longfei , Zhang Wengang
Published: September 2019

A reliability-based analysis method considering spatial variability of soil properties was proposed for stability analysis of pile-reinforced slope system in this paper. A total of 71 three dimensional (3D) finite element simulation results were used to develop a Polynomial Regression (PR) model relating the safety factor (FOS) of the slope system to the key input parameters. The PR model was proved to be reasonably accurate with a high coefficient of determination. It was subsequently implemented into a modified spreadsheet involving First-order reliability method (FORM) and spatial variability factors to perform spatial variability and reliability analyses. Based on the results, some useful conclusions are arrived with regard to the effects of spatial variability factors. In addition, a useful guideline for geotechnical engineers to choose suitable pile locations in engineering practices is provided.
Laboratory Study on Electrochemical Repair for Reinforced Concrete Exposed to Chloride ions Environment
Authors: Yan Li , Yongkun Qin , Wenxun Qian , Ning Xu , Xichang Zhu
Published: September 2019

Due to the “Ring-Anode” effect, reinforced concrete structures will shortly appear to have more serious corrosion deterioration after repairing by conventional rehabilitation methods in a chloride ion environment. Electrochemical repair methods have proved to be an effective and reliable technique for the protection of reinforced concrete structures, especially sacrificial anode cathodic protection (SACP) systems. In the study, active mortars were developed by adding polypropylene (PP) fiber and humectants. Adding PP fiber is intended to control the early shrinkage cracking of the active mortar, and increase the porosity of the active mortar for corrosion products to migrate easily. Using humectants intends to improve resistivity of the active mortar surrounding the anode and performance of the embedded sacrificial anode. The physical and electrochemistry performances of the active mortar were tested compared with the ordinary mortar. In the laboratory, a simulated chloride ions environment was used to evaluate the active mortar with a zinc mesh sacrificial anode for repairing and protecting the reinforcing bar from corrosion in a reinforced concrete column. The tested concrete column was submerged in the salt water and exposed to the air laboratory alternately. According to the criterion of cathodic protection (CP) for reinforced concrete, the reinforcing bars were protected effectively.
Development of Concrete Admixtures and Their Application in Road Bridges
Authors: Lu Mingyu , Ying Meng
Published: September 2019

Concrete admixtures, which is in order to distinguish mineral admixtures such as fly ash. In cement concrete, the technical and economic benefits of admixtures can be maximized. This technology has attracted attention at home and abroad and is now an indispensable part of concrete. The admixture can reduce the use of cement concrete in engineering, make concrete have more practical functions, and maintain good quality under various concrete engineering construction procedures to meet the individual needs of concrete during construction. Reduce the use of cement and reduce construction costs. This thesis is to study the types, properties, advantages and disadvantages of concrete admixtures, and applies the professional knowledge to studying the application of various concrete admixtures in road and bridge engineering to solve various concrete admixtures in real life. Some of the problems have made various concrete admixtures more widely used in road and bridge engineering.
Passive earth pressure under the log-spiral failure mechanism
Authors: Han Xiaofeng , Cai Zhenyin , Hou Wenang , Ruan Xiaobo
Published: September 2019

Under either convex or concave log-spiral failure mechanism, the passive earth pressure may be overestimated. This paper develops a new formula satisfying the moment limit equilibrium condition, which combines a new procedure to determine the passive earth pressure. The procedure could consider convex and concave log-spiral failure mechanisms simultaneously and figure out which failure mechanism is critical. The present method can investigate the influence of the inclination of wall, the slope of backfill or the wall friction on the shape of the critical slip surface. Additionally, the comparisons illustrate that the critical slip surface is concave log-spiral under certain conditions.
Comparison of different calculation methods for estimating scale of fluctuation of design soil properties based on indirect measurement data
Authors: Tian Mi , Sheng Xiaotao , Li Lihua , Zhang Fan , Xiao Henglin
Published: September 2019

Determination of scale of fluctuation (SOF) is a necessary prerequisite for describing the inherent spatial variability (ISV) of design soil properties (i.e., effective friction angle φ’) using a stationary random field in geotechnical reliability analysis. It is very important to select an appropriate method to enable an accurate estimate of SOF. However, it has been a challenging task due to the fact that the true SOF is actually unknown. In addition, when the number of direct test data of design soil properties are too limited to generate meaningful statistics, the design soil properties are indirectly estimated through transformation models which involve transformation uncertainty. This paper investigates the validity and accuracy of three commonly-used calculation methods (e.g., Bayesian approaches, mean average method, and fitting sample autocorrelation function (ACF) method) for estimating SOF of φ’ using indirect cone penetration test (CPT) data. It is found that Bayesian approaches provide more accurate estimates of λ of φ’ because it takes the transformation uncertainty from empirical regression models into reasonable consideration. The mean average method and fitting sample ACF method underestimate λ of φ’.
Stress Intensity Factors of Interfacial Crack with Arbitrary Crack Tractions
Authors: Hong Zhong , Li Chunlei , Li Hongjun , Guo Shengshan
Published: September 2019

Interfacial crack is much more complicated than a crack in homogeneous material. The crack is always in mixed-mode even for symmetrical geometry and symmetrical load, and the stress intensity factor has a complex value, which poses great challenges to numerical modelling. In some cases, there is surface traction on the crack faces, which can be crucial to the stability of the crack. In the presented research, a procedure is brought forward for analysis of interfacial crack with arbitrary surface traction based on the Scaled boundary finite element method(SBFEM). The surface traction on the crack is firstly divided into two parts, one in the direction normal to the crack face and the other in the tangential direction. Then each part is further divided into a series of power function of the radial coordinate. The solution for each can be solved semi-analytically by the SBFEM and is then superimposed to get the total solution. With this procedure, the stress and displacement are solved analytically in the radial direction, and the stress singularity at crack tip is obtained with high precision without refined mesh. Both anisotropic and isotropic materials can be considered. For validation of the procedure, a plate containing an interfacial crack and assuming different material propertes and different surface traction is investigated. Sensitivity analysis is also performed concerning the plate geometry and material properties. Finally the model is applied to solving the stress intensity factors of an interfacial crack of a gravity dam filled with water.
Fast assessment method for progressive collapse of RC frame structures
Authors: Zhong Bo , Zhang Ze-Jiang , Jiang Ya-Qiang , Zhu Hui , Huang Hao
Published: September 2019

Progressive collapse has attracted enormous research interests since the catastrophic 911 event. However, there is still a lack of fast assessment methods for assessing the damage state of structures suffering a certain initial local failure. In this paper, a newly developed efficient numerical model is introduced for progressive collapse analysis of reinforced concrete (RC) frame structure, and the reliability of the numerical model is verified by a collapse test. Then, the fast assessment method is proposed based on both the numerical model and energy approach. A 6-story RC frame structure is taken as an example, and three different initial failure scenarios are analysed by both the proposed fast assessment method and direct dynamic analysis method. Results indicate that although only one static analysis is required for the proposed fast assessment method, the accuracy is almost identical with that of direct dynamic analysis.
Seismic Aspects Regards Overbuilding on Masonry Heritage Buildings
Authors: Causevic Amir , Aksamija Lemja , Rustempasic Nerman
Published: September 2019

Nowadays, masonry heritage buildings usually experience changes during exploitation. In areas of emphasized seismic risk, in cases of extensions, alterations to the original dimensions, reconstruction (the removal of bearing elements, replacement of materials, introduction of new fittings), or the subsequent erection of properties close by, with a comparison of the foundation levels change of use, refurbishment, extension, or additional building to an existing building. It is necessary to analyze the seismic aspect of such interventions in seismic prone areas. At first, we’ll focus on the legal and technical regulations. For start we’ll look back at UNESCO’s Program on Masonry Heritage, then domestic and regional legal and technical regulations and with all of that we will define the first step of the process. Next step would be a detailed registration of the current condition of the building, and also determining the characteristics of the embedded materials. The load bearing structures of the building must also be accurately identified, with all relevant measurements and, in particular, a description of the building materials and their condition. This includes all detailed maps, plans, and details of the used materials, and especially detailed record of all the damages on the structure. Even at this early stage of investigative works it may prove necessary to secure certain structural elements, or even the entire building, to prevent it from collapsing. As a rule, this requires not only the removal of the outer cladding or even of parts of a wall to determine the depth of cracks but also, if there is any suggestion of subsidence, excavations around the building or to the depth of the foundations. Calculations, based on the planned and current condition of the building, will show whether the strengthening and rehabilitation are needed for the structure. The elements that need reinforcement or conservation can be identified during the initial visit, and provision can immediately be made to take the necessary steps to relieve the load. It is necessary to do all the steps regarding technical regulations, legal regulations, methods of approach, theoretical consideration, methods of calculation, and in the end to determine the needs of that building. Theoretical consideration regarding the determined condition of structure, from all the above aspects, is the next step to be done. This also includes evaluation of the viability of these interventions, based on experience. The most sensitive issue, without doubt, is determining the condition of the foundations. This should be addressed with the utmost care with the general opinion of the building’s stability in mind.
The Use of Lidar Data and VHR Imagery to Estimate the Effects of Tree Roots on Shallow Landslides Assessment
Authors: Alexander Vega Johnny
Published: September 2019

The study of geo-hazards has been benefited from the technological advances in the field of Remote Sensing (RS) techniques as the ALS (Airborne Laser Scanners) Systems with Very High Resolution (VHR) cameras. Recently, the LiDAR (Light Detection and Ranging) is an active sensor technique used for a variety of geoscientific applications including slope monitoring to retrieve ground surface displacements at high spatial resolution. Additionally, LiDAR has been widely used in order to collect high-resolution information on forests structure for the determination and characterization of vegetation cover due its ability to capture multiple returns and to reach the ground, even in forested areas, allowing the generation of Digital Terrain Models (DTMs) for the estimation of forest variables. In this paper, a LiDAR dataset and VHR imagery from aerial survey was used in the southwest zone of Medellín City-Colombia where the most frequent landslides are shallow and triggered by rainfall. Slopes with gradients up to 30% on residual soils characterize the study area, having about of 30% of forest cover consisting predominantly of Eucalyptus and Coniferous forests. For the estimation of the tree roots effects on the shallow landslides assessment on a natural slope, interpolation processes were developed from the LiDAR 3D point cloud, obtaining DTMs of 1 m-pixel. Additionally, orthophotos with the same spatial resolution were acquired in the aerial campaign. The proposed workflow was implemented on a GIS platform, and considers the extraction of the tree heights by generating a Canopy Height Model (CHM), while for the delineation of the tree crown a process of image segmentation was developed. Once the vegetation has been characterized using LiDAR products and dendrometric relationships, the Limit Equilibrium Method (LEM) was used to evaluate slope stability considering the effect of vegetation (trees). The results indicate that the proposed workflow allows to obtain adequate stability indicators for the estimation of tree roots contribution and additionally, this RS technique allows saving resources in this kind of analysis.
Specifics and Application of Wooden Constructions in the Agricultural Sector
Authors: Svajlenka Jozef , Kozlovska Maria , Posivakova Terezia
Published: September 2019

Over recent years farming has undergone fundamental changes and many aspects of the industry, including farm buildings, have been transformed thereby. Modern farm buildings are large and as cheap and maintenance free as possible reflecting the need for better performance and greater efficiency. These modern buildings however are much larger than traditional buildings and are constructed of materials which are not only artificial and ‘foreign’ to the area but are also very light coloured. As a result, modern economic buildings are characterized by specific features as traditional construction. Response to this trend are the modern methods of construction based on wood offering effective procedures (design and implementation of construction), resulting in a larger volume of products (production), with higher quality and with shorter time of their purchase. The aim of this paper is to present selected aspects of agricultural construction and their application at present.