bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Analysis of Damage to Retained Rock Mass of Dam Foundation Caused by Blasting Excavation
Authors: Liu Hong Yan , Wang Ming
Published: June 2011

On basis of the existed TCK model, the establishment process of a new rock blasting damage model is discussed by considering the relationship of crack density Cd, which indicates the shock damage extent of rock, and sound wave attenuation coefficient ap. Then, this model is inserted into the user-defined material model library of ANSYS/LS-DYNA3D software to construct the new damage model. Numerical simulation of damage to retained rock mass of dam foundation caused by rock blasting excavation in dam region with this model. Calculation results show that: as far as the blasting parameters and geological conditions in this paper, the damage to retained rock mass below caused by rock blasting excavation above is basically limited to the scope of 1.5m below the bottom of blasthole, and damage degree gradually reduces from the bottom of blasthole to faraway. Meanwhile, blasting will not cause rock mass to open along soft layer inside, whose maximum calculation displacement is only 3mm. The calculation result can be referred by the practical engineering.
Numerical Simulation on Rock Shock Accumulation Damage Effect
Authors: Liu Hong Yan , Zhang Hui
Published: June 2011

Shock accumulation damage failure of rock is often seen in engineering at present. The damage model based on stress wave attenuation is firstly adopted to improve the linear elastic constitutive relationship and load type used in original numerical manifold method program, then the influence of load intensity, action time and rock initial damage on accumulation damage is discussed with it. The simulation results show that: (1) Rock shock accumulation damage shows a nonlinearly rise with increase of load action time; (2) Rock shock accumulation damage shows a non-proportional rise with increase of load intensity, and there will be a load threshold which cannot produce accumulation damage; (3) The initial damage of rock has little influence on accumulation damage of time effect.
The Influence of Spalling on the Fire Resistance of RC Structures
Authors: Yu Xin Meng , Zha Xiao Xiong , Huang Zhao Hui
Published: June 2011

A great many of experiments has shown that reinforced concrete (RC) structures suffered from spalling in fire. However, at present there are still no convincing spalling predicting models available due to the inhomogeneous nature and complicated thermo-hydro-mechanical interactions in concrete at elevated temperatures. In order to evaluate the fire resistance of RC structures which are subjected to concrete spalling, a thermal analysis procedure is developed which considers the effects of spalling on the growth of temperature in RC members. The predicted temperatures are then used to model the structural behaviour. The spalled portion of concrete is modelled as "void", which has no thermal and mechanical properties. A series of parametric studies carried out on RC structural members with different boundary conditions shows that the influence of spalling on fire resistance is very significant apart from the RC slabs subject to higher laterally restraint.
Stability Analysis of Roof Structure with Steel Tubular Arch-Truss
Authors: Hu Sheng Jun
Published: June 2011

Based on the stability theory, one roof structure with steel tubular arch-truss was taken as a research object. Linear buckling, geometric nonlinear stability and elastic-plastic nonlinear stability were investigated by applying ANSYS finite element software, and the relational curves of critical load-displacement were obtained. The analysis results show that material nonlinear makes obvious influence on the stability of the structure, material nonlinear and geometric nonlinear are taken into account at the same time can make a better understanding of the structural stability performance.
The Construction Technology of Light Masonry Retaining Structure Used in Fluctuating Belt of the Three Gorges Reservoir Area
Authors: Cheng Long Fei , Li Lin Yan
Published: June 2011

Masonry retaining structure consists of precast concrete blocks, which has good looks and is in harmony with environment. Blocks with proper shape can be used in fluctuating belt of the reservoir area. The construction of masonry structure should conform to the following steps: first, excavate the foundation ditch, lay a cushion and arrange the controlling points, insuring the quality of the first layer of blocks; it would be better to choose inorganic coarse-grained soil as filler and to set a water filtering layer with a height more than 30cm behind the retaining wall; carry on the construction of earth filling behind the wall after the blocks are fixed as requested, and then fix the geotechnical grille when the height of earth filling reaches the elevation of the grille; put Geotechnical Fabric between permeable aggregate and the earth filling behind it to keep the two materials from mixing.
Nonlinear Finite Element Analysis on the Steel Frame with Semi-Rigid Connection under Periodic Load
Authors: Wang Lai , Liu Bo Shun , Yang Ning
Published: June 2011

In this paper, nonlinear finite element analysis on the steel frame with top-seat angle and double web-angles semi-rigid connection were carried out with ANSYS finite element software. In the analysis, connective, geometrical and material nonlinear were considered. Compare analysis results with experimental results, the influence of semi-rigid connection’s flexibility on steel frame was studied and some references to the design of steel frame with semi-rigid connection were supplied.
A New Similarity Experimental Method of Carbonation Assessment on Concrete Structures
Authors: Jin Li Bing , Xiong Xiao Li , Xiao Zhao Ran , Dong Cheng Ying
Published: June 2011

In order to evaluate and predict the behaviors of concrete structures under the normal atmospheric conditions, a new similarity experimental method is presented which can evaluate the field performance of reinforced concrete (RC) structures by measuring the structure in the artificial accelerated environment. The causes of concrete structural damage and the social harm caused by the RC structural durability failure were analyzed. The current status of concrete carbonation was described. The method establishes the similarity-relationship of performance changing between the field and the accelerated environmental conditions by contrasting and analyzing the behaviors changing under both environments, and realizes the effective and exact estimate to the field structures from the indoor accelerated experiments. It brings forward a new way of thinking to test the RC structures under the atmospheric conditions.
Design & Research of Large Height Lifting Mechanism for Ultra-Large Structures
Authors: Sun Tao , Zhang Qing , Liu Ming
Published: June 2011

A current development trend of the industrial equipment is ultra-large scale. The construction, transportation, and installation of these equipments require ultra-large tonnage lifting equipments. At present, domestic ultra-large tonnage lifting equipments, particularly for special purpose are still immature, unable to meet requirements of the lifting of ultra-large structures. Based on the need of ultra-large steel structures (offshore oil platforms) lifting, using strength theory and finite element analysis, a continuous lifting mechanism for the lifting of ultra-large structures was designed in this article. The continuous lifting mechanism consists of two parts: the mechanical support structures which was designed in this article, and the hydraulic system. The main characteristics of the mechanism are: the framing truss structure assures large height lifting; and the accumulated of synchronous blocks achieves large height lifting.
Assessment of Serviceability Based on Corrosion Cracking during a Long-Term Chloride-Induced Corrosion
Authors: Zhang Rui Jin , Yang Hui Lin
Published: June 2011

In this paper, a non-destructive analytical method was proposed to predict the serviceability of corroded RC structure from corrosion cracking. Two models of corroded reinforced concrete were proposed to take into account the influence of corrosion pattern. Based on a three-phase model linking corrosion cracking and reinforcement corrosion and the transfer length, the models allowed quantification of the effect of the steel cross-section loss and the deterioration of the steel-concrete bond. Using a macro-element FEM analysis, the serviceability models were performed on a corroded beam stored in a chloride environment under sustain loading to predict the deflection of mid-pan under service load and compare with the experimental results.
Multiple Anchor Behavior of Steel-to-Concrete Connections under Reversed Cyclic Loading
Authors: Xie Qun , Sheng Qin Zhu , Ju Hao Xue
Published: June 2011

Four steel-to-concrete connections with adhesive anchor groups under reversed cyclic loading have been tested. The results showed that anchor steel could reach yield strength before connection failure, generating small shell-shaped concrete cone in the surface of block and the ultimate capacity was governed by strength of anchor. Seismic characteristics of hysteresis curve, rigidity regression, ductility and energy-dissipation were used to draw conclusions that the connections would behave in a ductile manner without significant loss of loading capacity after peak value and visible deformation could develop until failure occurred. Increased embedment depth and added amount of anchors were helpful to improve seismic performance of connections. Only the outer row of most stressed anchors in the tension zone were needed to meet the elliptical interaction of tension and shear capacity requirement during the design process of anchor groups under combined shear and moment loading. In seismic design of steel-to-concrete connections, the predicted capacity by a reduction factor of 0.8 was advised and the comparison of calculated versus observed capacity presented limited variance.
Experimental Research on Axially Loaded Circular Concrete Columns Confined by CFRP under Preload
Authors: Pan Yi , Cao Shuang Yin , Jing Deng Hu , Zhao Shi Chun
Published: June 2011

A total of 32 circular-section concrete columns confined by CFRP sheet were tested in uniaxial compression involved in different preload ratio, concrete strength and CFRP plies. The failure characteristic and mechanics behavior of confined concrete columns were presented, and the descending of the peak stress and strain of confined concrete due to preload were analyzed. The experimental results indicated that the confinement effect of CFRP was influenced by preload ratio observably. The second stiffness, the peak stress and strain declined with preload ratio ascending, and the extent developed with the enhancement of CFRP ply.
The Experimental Study on Realkalization Repair for the Durability of RC Structure after Fire
Authors: Xiong Yan , Wu Di
Published: June 2011

The damages to reinforced concrete structures subjected high temperature of fire mainly include the followings: high temperature make the microstructure of concrete be loose and porous, the strength of concrete and steel reduce greatly.The alkaline hydration products of cement was decomposed under the high temperature, which would destroy the alkaline environment of concrete around steel and cause the steel corrosion. In this paper, the machanism of realkalization technique is present. Moreover, method of mercury intrusion pore measurement, SEM analysis and investigation on pH Value of concrete pore solutions experiment were carried out to study the durability repairing efficiency of realkalization technique.
Modelling and Analysis of the Bottom Frames of Multi-Story Masonry Buildings Exposed to Fire
Authors: Yan Kai , Zheng Wen Zhong , Wang Ying
Published: June 2011

The multi-story masonry buildings with reinforced concrete frames on ground floors collapse more easily than pure frames when bottom frames exposed to fire, for reasons that fire load of its ground floors is relatively large, and the ratio of dead load to the total loads is also large, deformations of joists caused by fire produce adverse effect on arch mechanism of masonry. For the purpose of loading temperature on steel bars and concrete for fire resistance analysis of reinforced concrete structures in ABAQUS, separated loading method is proposed firstly in this article. The Hill yield criterion for compression and the Rankine yield criterion for tension are adopted to establish anisotropic elasto-plastic material model for masonry. The process simulation from temperature rises to buildings collapse is realized. A parametric study is conducted to investigate the effects on fire resistance of the bottom frames when the bottom floors exposed to fire due to the change in effective load ratio, section size and reinforcement ratio. The study shows that the failure mode of the bottom frames exposed to fire is mainly due to columns collapse. Bottom fames designed with seismic class I and II have relatively more safety storage than non-seismic designed bottom frames to resist the fire load effect, and they can satisfy time limits of fire resistance.
Causes and Control of Crack in Residential Building Designing
Authors: Yan Jing , Yang Hong , Liu Feng
Published: June 2011

With the development of commercial concrete, the problem of crack has become a difficulty puzzling the engineers. From the view of design ,this paper discussed specially on the problem of residential building’s crack, analysed some faulty and incomplete acts which will cause cracks ,and presented some corresponding control measures.
Several Written Instructions of the Technical Regulation of Shot-Pier Shear Wall Structure Key Figures Construction
Authors: Liu Jin Sheng , Liu Shi Mei
Published: June 2011

As a new type of resist lateral force structure, short-pier shear wall structure has been widely used in high-rise and super-tall residential construction. However, at present, there isn’t a specifically targeted short-leg walls structure design and construction technical regulations both at home and abroad, which led to the architectural engineering design and construction market turmoil. By the prophase research of the short-leg walls structure seismic performance, and a great deal of experiments, combine with the latest research results at home and abroad, adopt the limit state design method based on probability theory, the paper clarifies the definition of short-leg walls, and analyzes the calculation method of section load-carrying capacity for earthquake combination and no-earthquake combination, which has certain directive significance and engineering application for the design and construction of high-rise residential buildings.
Brief Analysis of Temperature Effect on the Low Pier Continuous Rigid-Frame Bridge
Authors: Wu Hai Jun , Zhang Hao , Lu Ping
Published: June 2011

This paper was based on a bridge project in Chongqing. Finite element software was applied to analyzed the influence of the annual temperature on the pier of continuous rigid-frame bridge with the height parameter change of the pier by analyzing the computing results, this paper summarized the temperature effect on low pier of continuous rigid-frame bridge. It was concluded that the height of the pier was the major factor of the temperature effect on the pier internal forces of the rigid-frame bridge. The lower the pier was, the more obvious the effect of temperature, to some extent, the temperature effect on the pier even exceeded the self-weight effect.
Analysis of Sensitive Factors of Long-Span Continuous Rigid Frame Bridge’s Stability with Thin-Wall Piers in the Construction Stage
Authors: Wu Hai Jun , Kang Yu Qiang , Zhang Lei
Published: June 2011

Analyzing the basic theory of stability, with a high pier of large span prestressed concrete continuous bridge as the example, the stability was analyzed when constructing, considering wind load, hanging basket, pier etc. Both eigenvalue and mode are got for the longest cantilever ting condition, the sensitivity of stability to various loads being analyzed. It is concluded that the unbalanced weight and the falling of basket are the main factors.
Concrete Beams Strengthened with Prestressed Near Surface Mounted Helical Rib Steel Wire
Authors: Ding Ya Hong , Zhang Mei Xiang , Zhang Chun Sheng
Published: June 2011

This paper presents research on 13 beams with nonprestressed and prestressed helical rib steel wire bonded in sawed grooves in the concrete cover under monotonous loads based on the lack of old strengthening methods. The prestressing, stressing process, first-crack load, steel-yielding load, ultimate load at failure and deformation are systematically studied. The results from the tests show that this new strengthening technique using helical rib steel wire bonding in the concrete cover is an efficient method, which can overcome the problems with peeling of the strengthening material when the surface bonded FRP laminates, also overcome the shortages of nonprestressed beams. The prestressed beams exhibited higher first-crack load, higher steel-yielding load, as well as a larger deformation capacity as compared to nonprestressed strengthened beams, which is important for a construction's lifetime; the fatigue behavior will improve and as a consequence the crack widths will be smaller, which can result in increased durability, which should indicate a more advantageous behavior in the service limit state (SLS). However, the ultimate load at failure is as high as nonprestressed beams, but in relation not as large as for the cracking and yielding. The ultimate load at failure is also higher as compared to non strengthened beams. The results provide a reference for engineering application.
Investigation on Shear Creep Mechanical Properties of Soft Rock
Authors: Wang Yu , Li Jian Lin
Published: June 2011

The construction of slope or underground engineering often encounters soft rocks, which control the stability of rock engineering, with obvious characteristics of rheology. Under step load conditon, the shear creep test of argillaceous siltstone is performed by using the RMT150c rock and soil mechanics testing machine. Testing results show that the amount of creep deformation for argillaceous siltstone is big enough, which should be taken into consideration for analysis of stability or design of slope or underground engineering. Based on testing results, the long-term shear strength parameters are determined to provide theory basis for engineering survey and design.
Soil Water Characteristic Curve and its Applications in Tunnel
Authors: Yang Yu You , Zhang Qin Xi , Wang Gui He , Yu Jia Xing
Published: June 2011

A soil water characteristic curve (SWCC) can describe the relationship between unsaturated soil matric suction and water content. By analyzing and researching the test data of the soil water characteristic curve researchers can initially establish the SWCC equation and apply this equation to the actual engineering analysis. In another words, this article is based on the fluid-solid coupling theory of unsaturated soil used to analyze and study the problem of land subsidence caused by tunnel construction. Numerical calculations show that the coupling results agree well with the measured curve works.
Energy Analysis for Energy Dissipation Shed-Tunnel’s Rockfall Impact Signal
Authors: Wang Lin Feng , Tang Hong Mei , Chen Hong Kai
Published: June 2011

Shed-tunnel is one of common prevention measures along the highway. First, denoised the rockfall impact signal when the rock impact the ordinary shed-tunnel and the energy dissipation shed-tunnel by the wavelet theory. The calculation result indicated that the wavelet theory’s denoise effect is very good. Then, pick-up each frequency band’s the rockfall impact signal, and analysed the energy for each frequency band’s impact signal. The result indicated that the energy dissipation shed-tunnel’s impact energy concentrate in the low frequency part. There are only 0.4% impact energy in the high frequency part. Besides, the energy dissipation shed-tunnel’s impact energy in the low frequency part is higher than the the ordinary shed-tunnel, and the energy dissipation shed-tunnel’s impact energy depressed velocity when the impact frequency increase is fast than the ordinary shed-tunnel. So the energy dissipation shed-tunnel’s design must consider the low frequency impact,and could ignore the high frequency impact.
Performances of Compressive Capacity for Belled Wedge Pile Group
Authors: Kong Gang Qiang
Published: June 2011

The belled wedge pile, which can improves the friction of pile shaft, tip resistance and reduce the influence of negative skin friction, is introduced. In this paper, the accuracy of FLAC3Dmodel is verified with field load test results. Subsequently, the numerical model was used to study the compressive behavior of belled wedge pile, conventional belled pile, wedge pile, and uniform section pile with the same concrete volume. Furthermore, the compressive behavior of belled wedge pile group was studied in terms of influencing factors such as pile spacing, stiffness of soil at the pile end, and diameter of enlarged pile head. The numerical results show that the compressive advantages of belled wedge pile can be developed adequately when the distributions of the friction of pile shaft and pile tip resistance are equilibrium, and it increases with increasing pile spacing, increasing stiffness of soil at the pile end, and increasing diameter of the enlarged pile head.
Simulation for the Complete Uninterrupted Penetrating Process of Jacked Pile
Authors: Lu Qun , Zong Jin Hui , Zhang Jian Xin
Published: June 2011

The FEM mehods for simulating the penetration of jacked pile were summarized. Using the displacement penetration method, the complete uninterrupted penetrating process of jacked pile was simulated with the finite element method based on ANSYS. The soil’s displacement and stress field were obtained, and compared with the field test. The elastoplastic constitution law, large deformation, soil’s gravity field and pile-soil friction contact were taken into account. The difficulties and skills in the simulation were indicated, so it might be helpful to the other researchers.
Study of Seismic Design Method for Frame Supporting Structure with Prestressed Anchors
Authors: Dong Jian Hua , Ma Wei , Zhu Yan Peng
Published: June 2011

Frame supporting structure with prestressed anchors is a new anchoring technology applied in slope reinforcement in recent years. Its dynamical analysis and seismic design is a big challenge, a set of systematic calculation methods can not be found for the time being. This paper shall first evaluate the calculation formula of anchoring slope earthquake earth pressure, then establish dynamic calculation model of frame supporting structure with prestressed anchors, solve using FORCE METHOD, finally apply the proposed method in engineering project. The result shows that this method is applicable to loess areas with uniform soil texture, providing the theoretical basis for seismic design of frame supporting with prestressed anchors.
Static Mechanical Properties and Impact Resistance of Steel Fiber Reinforced High-Strength Lightweight Aggregate Concrete
Authors: Song Hong Wei , Wang Hai Tao
Published: June 2011

Since high strength of lightweight aggregate concrete leads to increased brittleness, fiber reinforcement should be considered for improving strength and ductility. 5 groups of SFLWC specimens with different steel fiber volumes including 0.0%, 0.5%, 1.0%, 1.5% and 2.0% were tested to investigate the effect of steel fiber content on the static mechanical properties and impact resistance of lightweight aggregate concrete. The static mechanical properties include the prismatic compressive strength, splitting tensile strength, first-crack flexural strength, flexural strength, and flexural toughness, etc. The experimental results indicated that addition of steel fiber can greatly improve such mechanical properties as the splitting tensile strength, flexural strength, flexural toughness and impact resistance, but leads to a little effect on compressive strength. Further more, the author suggests the feasible volume ratio of this kind of steel fiber is 1-1.5%.
Predication and Analysis on Ground Settlement Induced by Shielding Tunneling Construction
Authors: Sun Hai Xia , Zhao Wen , Yu Jian Jun
Published: June 2011

This paper takes Shenyang metro engineering with sandy soil for background, and the ground settlement induced by shielding tunneling construction is predicated and analyzed. Make clear the influential areas of lateral settlement in accordance with the monitoring data. Use traditional Peck Formula to fit actual settlement curve of the cross-section. From the curve fitted by Lagrange interpolation function, the half width i of the settlement tank can be gained. And then calculate the volume of the settlement tank, the improvement factor k and volume loss rate VL. The Peck Formula with improved factors can suitably predict the ground surface settlement.
Radon Anomaly Analysis of Engineering Slopes
Authors: Wang Xiao Qun
Published: June 2011

For various engineering slopes, due to unloading relaxation of the rock mass or sliding disintegration of the slope, the cracks inside the slope will open by different extent, thus when measuring radon content, different parts of the slope will have different radon content anomaly. Through analyzing radon content anomaly, information as the landslide boundary and structure zoning of the slope rock mass, etc can be obtained. Landslide boundaries and rock mass structure zoning and other information can be identified because of radon anomalies analysis. Through radon anomalies analysis on two projects, landslide boundary identification and zoning on bank-slope adit rock mass structure, it has proved that radon anomalies analysis could be well used as a complementary method to provide more analysis data and thus provide objective scientific basis for slope stability study. The analysis method used is simple, easy to operate, and low in cost. In the analysis, it shall be noted that removing interference from groundwater, desiccant humidity should be excluded.
Restoration of Tunneling Failure in Kaohsiung MRT Project
Authors: Lo Wei , Chang Po Shou
Published: June 2011

According to past experiences, the collapse of tunneling work always triggered a chain reaction of collateral damage and caused a considerable urban impact. Therefore, while the tunnel disasters occur, the timely response is important to prevent the expansion of the disaster and the subsequent restoration work is equally important to shorten the impact duration and ensure the ultimate success of the project. This study used the restoration works of a tunneling failure that occurred in Kaohsiung MRT project as a research subject to identify those works, which are critical to the success in the process of the restoration. The research results suggest that an accurate site investigation, and a thorough analysis of possible alternatives and the selection of restoration methods with comprehensive consideration of various factors are the critical factors for the success of the restoration works.
Experimental Research on Rheological Properties of Cemented Mortar in Tail Void Grouting of Shield Tunnel
Authors: Yuan Xiao Hui , Han Yue Wang
Published: June 2011

Grout flow pattern and rheological parameters determine grouting pressure transfer process in annular tail void and filling rate for shield tail void. However, cemented mortar is a mixture of cement, fly ash, sand, bentonite and water, which lead to grout rheological properties and rheological parameters are difficultly determined. Based on orthogonal experimental design method, grout rheological properties were tested by rotational viscometer. Utilizing variance and poly-nonlinear regression analysis, the qualitative and quantitative relationships between mix ratios and rheological parameters were obtained respectively. It is shown that cemented mortar flow pattern commonly agree with Bingham fluid type, and plastic viscosity varies between 1 and 4Pa•s, and shear yield stress varies between 10 to 40Pa respectively. Water-binder ratio and bentonite-water ratio are key influencing factors for grout rheological parameters. With the water-binder ratio increasing and bentonite-water ratio decreasing, plastic viscosity and shear yield stress present reducing tendency.
Influence Analysis of Pit Foundation Precipitation to Adjoining Raft Foundation
Authors: Sun Zong Jun , Liu Xiao Bin , Wu Yan Kai , Luan Qian Chao
Published: June 2011

Pit foundation excavation leads both settlement and uneven settlement in the building foundation. It has settlement cracks in masonry and concrete structure; these damages lie on the basis of the instability in neighboring buildings. In this paper, by the use of FLAC3D, it establish three-dimensional numerical analysis mode of interaction between foundation pit excavation and raft foundation, the change patterns of the soil deformation, pore water pressure and the uneven settlements of raft foundation are analyzed. The results indicate that the maximum value of the raft foundation settlement appears on the maximum pit free surface on the foundation pit, and the lesser value of the raft foundation settlement is away from the foundation pit, these indicate that the laws of the uneven settlement.
Improving the Predictability of Hiley Pile Driving Formula in the Quality Control of the Pile Foundation
Authors: Tokhi Hamayon , Ren Gang , Xie Yi Min
Published: June 2011

Pile Dynamic Formulas are the oldest and frequently used method to determine bearing capacity of piles. The more recent method is based on the Wave Equation analysis and different formulations such as Case Mathod, TNO, CAPWAP and TEPWAP which were developed for pre-driving analysis and post-driving measurements applications. The major factors for the common use of the dynamic formulas have been due to their simplicity, cost effectiveness and applicability in various piling situations. However, in some literature the energy approach have been given an unfair reputation as being unreliable and less accurate than the more analytical or dynamic testing methods. One of the issues due to the poor performance of the dynamic formulas is that, historically, the hammer energy and the energy trasferred to pile had to be assumed. Nevertheless, with the advent of computers, new technologies are emerging with the advancement in construction industry. This has produced gradual improvements that have resulted in the dynamic method to be used on many projects with greater reliability. In this paper, a review of the different testing methods as well as pros and cons of the pile driving formulas are discussed. Also, an approach to improving the widely used Hiley dynamic equation is presented. This approach enables evaluation of the pile capacity to be made more accurately.
Pile Bearing Capacity Improvement by Post-Grouting on Tip and Side
Authors: Liu Ji Feng , Cui Xiu Qin
Published: June 2011

For verifying pile bearing capacity improvement by post-grouting on tip and side and the decrease of building settlement, 10 tip and side post-grouting and 2 unpost-grouting piles are tested by low strain dynamic test, static loading test, stess distribution monitoring and high strain dynamic test, and the building settlement is monitored. It is indicated that all piles length and integrity are meeting the challenge, the post-grouting piles bearing capacity are at least 70% improved than that of unpost-grouting piles, designing pile bearing capacity as 8800kN is safer, the building maximal settlement and the differential settlement is satifying. The preliminary designed 904 piles are reduced to 531 by adopting post-grouting technique and about 20% cost of pile engineering is saved, the proper grouting stata choosing, the accurate grounting volume and pressure controlling in the post-grouting constrution process are needed.
Effects Analysis of Expansive Soil Slope Reinforced with Geogrid Considering Long Term Weathering
Authors: Sun Ji Zhu , Xiao Wen Hui
Published: June 2011

Considering the long-term atmospheric weathering effects on expansive soil strength, geogrid reinforcement effects of expansive soil slope are analyzed with FLAC3D. The research in this paper shows that: (1) when the reinforcement is deeper than the weathered layer, the inhibition effect of soil stress and displacement increases with increasing length of geogrid, in this case a critical slip arc moves away from the slope surface, and the maximum safety factor of slope stability increases approximately 50 percent; the grid stress decreases with the increasing height of grid location; (2) when the reinforcement depth exceeds the weathered layer 1 m, the denser geogrid in the vertical direction, the smaller shear stress and horizontal deformation in reinforced region, so that the slope safety factor increase and the critical slip arc moves towards the slope back. However,if the geogrid length exceeds the weathered layer more than 3 m, the vertical grid distance change has no significant influence on the safety factor and the location of critical slip surface.
Experimental Study of Engineering Behaviors on Improved Expansive Soils in the Xinqiao Airport Runway of Hefei
Authors: Wang Ming Wu , Ge Kang , Zhu Da Rong
Published: June 2011

Foundation treatment of expansive soils is a complex worldwide problem. Herein engineering behaviors of expansive soils and improved expansive soils with lime (IESL) in the runway area of Xinqiao international airport of Hefei were investigated by means of laboratory experiments and field tests. It was concluded that the expansive soils of mean plasticity index 24.2, and optimum moisture content of 16% in the engineering area, behaved weak and medium expansive potential. The plastic index of improved expansive soil of 7% lime mixed indoor and of 8% lime incorporated on site dropped to 20 and 13. At the same time, the free swelling ratios of IESL reduced up to 6.31 % and 3% relative to 46.5% of expansive soil, and the swelling pressure also decreased from 67.5 kPa to 4.05 and 11.28 kPa, respectively. The mean unconfined compression strength of improved expansive soil of 7 % lime on site was 853 kPa, 71% stronger of that of expansive soils. And the soil response modulus was up to 235.2 MN/m3, 9 times of expansive soils. It was also found form the immersion tests on site that the swell value of IESL was only 30% at most of expansive soils at the same depth. These results indicate that the compacted IESLs have a good bearing capacity, strength and water stability, so the engineering behaviors of IESLs are much better than those of expansive soils, and prove that the modification plan, expansive soils incorporated 7% lime on site could meet the design requirements.
Testing of Strength Parameters and Deformation Parameters of Surrounding Rock and their Distributions
Authors: Yan Chun Ling , Ding De Xin , Tang Yi Qun , Bi Zhong Wei
Published: June 2011

Cores were taken from the hanging wall of the III -1 ore body at Kangjiawan Lead, Zinc and Gold Mine. 50 samples for compression and tension tests were fabricated. 50 compressive and 50 tensile strength values were obtained by RMT-150B testing systems. The probability distributions for the compressive and tensile strength were tested by the hypothesis test method. It proves that uniaxial compressive strength follows normal distribution and tensile strength follows the lognormal distribution. And it proves that elastic modulus and Poson’s ratio follow normal distribution. 50 pairs of cohesion and internal friction angle were obtained by randomly drawing a uniaxial compressive and tensile strength samples from 50 measured values. Cohesion follows lognormal distribution and internal friction angle follows normal distribution through hypothesis test method. With the results, some references can be conveniently provided for prediction of the strength and distribution of similar rocks in related geotechnical projects.
Online Measurement and Quick Replacement of Pipeline Segments in an Offshore Platform
Authors: Zhang Shi Liang , Yan Jin
Published: June 2011

Due to the effect of deterioration and corrosion, large amounts of oil and gas pipeline segments need to be replaced in offshore platforms every year. By using traditional reconstruct method, it needs to stop production in offshore platform firstly, then follows insulation, backout, baiting, jointing, installation, pressure test for tightness, etc. This process will take a long time and much work, and it will greatly influence the regular manufacture of oil and gas. In this work, a new method is introduced that oil and gas pipeline segments are replaced without stopping production. The technology includes precisely measuring geometry dimension of the oil and gas pipeline segments to be replaced, making prefabricate replacement segments exactly offline, and replacing the pipeline segments on site in a speedy and safety way. Last, an engineering applications case is given to show the whole detail process. It proves that the technology not only makes great progress in pipeline reconstruction, but also results in good social and economic benefits.
Study on Stability of Consequent Rock Slope by Simulation Experiment
Authors: Huang Ping Lu , Chen Cong Xin
Published: June 2011

Based on similarity theory, the geologic mechanics model is established and to be used for studying distortion and breakage mechanism of consequent rock slope. The paper introduces the design and process of the experimentation. Through experimentation of a slope model, the stability of a slope is studied. After analyzing the phenomenon and data of the experimentation, it is found that the major deformation model is slippage. The mode of breakage is sliding and fracturing. The process of slippage is graded. The more hinder the position of coast is, the smaller the obliquity of rip face is. The deformation and breakage of bedding slope firstly arises at the dig face near the earth's surface.
Experimental Study on Timeliness of Pullout Force of Grouting Soil Nailing
Authors: Wang Kui Yang , Ji Hong Guang
Published: June 2011

Pullout force of grouting soil nailing is a key to support. This test revealed that limit pullout force of soil nailing increased with the time. The timeliness function was asked for by Origin software. It's the cause for many failure accidents in soil nailing support engineering. But it was often neglected in engineering design and construction.
Geographical Information System of Soil Investigation Data for Construction Purposes
Authors: Uthayopas Prapat , Wongvanichtawee Chalermkiat , Bhundularp Prayooth
Published: June 2011

Field soil investigation prior to the foundation design of any structure is a must for the design engineer. Since the cost of such operation is rather high, then it is sometimes impractical. The design and the preliminary cost estimation of the construction are then impossible to be prepared. This paper applies Geographical Information System – GIS via Google earth to all over Bangkok area thus enables engineer to retrieve the physical characteristics of soil layers from the existing soil data. In addition, utilizing the feature of Google earth can be illustrated more visibility in the required position of boring log and position of retrieved soil boring log data. Moreover, it can be applied to everywhere around the world.
Consolidation Theory for Composite Ground with Granular Columns Based on Different Calculation Models
Authors: Zhang Yu Guo , Bian Ya Dong , Xie Kang He
Published: June 2011

The consolidation of the composite ground under non-uniformly distributed initial excess pore water pressure along depth was studied in two models which respectively considering both the radial and vertical flows in granular column and the vertical flow only in granular column, and the corresponding analytical solutions of the two models were presented and compared with each other. It shows that the distribution of initial excess pore water pressure has obvious influence on the consolidation of the composite ground with single drainage boundary, and the rate of consolidation considering the radial-vertical flow in granular column is faster than that considering the vertical flow only in granular column.
Analysis into How to Determine the Spring Constant of Groundwork in Design of Underground Structure
Authors: Li Ying Min , Wang Lu , Liu Li Ping
Published: June 2011

Based on the Winkler's hypothesis, this paper discusses how to determine the spring constant of groundwork in design of underground structure. When no sufficient experimental conditions are available, the method of numerical calculation can be used to determine the value of spring constant of groundwork. The resulted value is basically the same as the value of experience from the engineering criterion.
Preliminary Study on the High-Pressure Equation of State of Concrete
Authors: Jiao Chu Jie , Jiang Guo Ping , Gao Le
Published: June 2011

The shock Hugoniot relationship of concrete was studied based on concrete test subjected to the high-velocity impacting loading by one stage gas gun. The P-U(pressure-partical speed) shock Hugoniot relationship curve of concrete was gained from the D-U(shocking wave speed-partical speed) curve of concrete, and the equation of volume pressure P and volume strain v was put forward according to the example analysis. Moreover, based on the polynomial Grьneisen equation, the parameters of high-pressure equation of state of concrete were got by fitting the test date, and the theoretical values from the equation matched well with the experimental ones.
Quantification Studies on Meso-Damage Characteristics of Marble under Uniaxial Compression Condition
Authors: Ni Xiao Hui
Published: June 2011

The damage and failure of rock under loading are caused by the propagation and coalescent of cracks at mesoscale, so it is helpful to understand the mechanical behaviours of rock by quantitatively investigating on mesostructure of rocks. Based on the theory of damage mechanics, a digital experimental system on rock meso-structure is proposed. In this paper, the digital studies are conducted on the meso-structure of the marble from Jinping, Sichuan with the damage theory. Lots of meso-structure images are obtained through SEM observation. Based on digital image processing theory, some meso-level characteristics of micro-cracks are obtained such as length, azimuth, width, area and circumference. With the statistics theory and the Monte Carlo theory, the meso-level information of micro-cracks and their morphology are simulated in the representative volume element (RVE) of the Jinping specimen.
Experimental Study on Dewatering Dredged Clay with Ventilating Vacuum Method
Authors: Ji Feng , Ding Jian Wen , Hong Zhen Shun , Gui Yue
Published: June 2011

A series of model tests were performed on dredged clay with high initial water contents for investigating the dewatering behavior by ventilating vacuum method (VVM). The results shows that the surface water separated from dredged clay can be quickly removed by VVM in which a new pattern PVD is used. In addition, the method also speeds up the deposition of dredged clay. The volume of dredged clay with an initial water content of 4.5 times liquid limit decreases by 50 percent within two months. This paper also investigated the spatial distribution law of water content by TDR method. It is found that the drainage distance of PVD is about 0.3-0.4m.
The Study on the Ratio of Similar Material in Landslide Model Test
Authors: Liu Xiao Ling , Wang Shi Mei , Tan Yun Zhi , Hu Xin Jiang , Zhao Dai Peng
Published: June 2011

The choice of similar materials and the design of mix proportions is a key step in landslide model test. On the basis of experiment, we conduct a research for the similar materials which may sufficing volume weight, cohesive force, angle of internal friction, deformation modulus, and the infiltration coefficient on the same time. Then we put forward two kinds of schemes: one is the mixed material of high-strength glass micro beads and talcum powder; the other is the mixed material of lead beads, river sands, rubber powder and talcum powder. By analyzing the result of mix proportions test, We concluded the regularity that similar index varies along with different content of the similar material ingredients and found the notable influence factors , which provides important reference for the components of similar materials in the landslide model test.
Constitutive Equation of Expansion Rock under Humidity Field
Authors: Ji Ming , Zhang Nong
Published: June 2011

The weight and length, width and height of three directions of cuboids’ type calcareous mudstone after infiltrated with water in different period of time were measured by using electronic balance and vernier caliper. The results show that the calcareous mudstone expansion strain is proportional to volume and mass water content. Mchanical properties of calcareous mudstone were studied by uniaxial compression experiments of calcareous mudstone with different water content which carried out by using microcomputer controlled electro-hydraulic servo compression testing machine control system of YAW series. It is concluded from experiment result that calcareous mudstone is brittleness with low water content but when water content reaches saturation, calcareous mudstone presents plastic features. Based on the results above, the constitutive equation of rock considering humidity field is derived which provides important guiding significance to engineering practice.
Research on the Mechanics Characteristics of Loess Tested by a New True Tri-Axial Apparatus
Authors: Shao Sheng Jun , Luo Ai Zhong
Published: June 2011

All true tri-axial experimental apparatuses are usually applied to test the mechanics characteristics of soils under complicated stress conditions. Because of the analysis of non-rationality of three kinds of chamber framework developed in past, a new true tri-axial apparatus with a new structural chamber is recently developed by the institute of geotechnical engineering, Xi’an University of Technology. The mechanical description of a new tri-axial apparatus for soil testing is presented herein. The design of new tri-axial apparatus took into the flexibility in adjusting sample size, convenience in assembling sample and easily controlling of three normal stress conditions. The stress-controlled and strain-controlled performance of experiments can be accomplished respectively in the new true tri-axial equipment, which is of a special chamber. The special chamber includes of four cells with bursa filling liquid, being corresponding to four lateral surfaces of cubic sample respectively, separated by steel clapboards. The steel clapboards can turn freely on the horizontal plane and flex in the radial direction so as to adapt to the displacement of sample corner. Through the true tri-axial testing of remolded loess and intact loess were executed on the new true tri-axial apparatus, and the characteristics of stress-strain curves for the true tri-axial tests of remolded loess and intact loess were analyzed under different intermediate principal stresses. The characteristics of the new true tri-axial apparatus are as following: structure is simple, and operation is well-suited, and stress state is real, and strain measurement is accurate, and testing process is controlled easily.