influence of nonplastic fines on shear wave velocity based assessment of liquefaction many false positives no liquefaction detected when the normalized shear wave velocity cyclic stress ratio vs1 csr combination indicated that it should have been are observed in the database used in the simplified liquefaction assessment procedure based on shear wave velocity two possible reasons for false positives are the presence of a thick surface layer of nonliquefiable soil and the effects of fines on cyclic shear resistance crr and vs1 about 67 of the false positives that could not have been caused by an overlying thick surface layer are associated with silty sands with less than 35 fines the effects of fines on the liquefaction resistance of silty sands and on the shear wave velocity are analyzed theoretical crrfield versus vs1 curves for silty sands containing 0 to 15 nonplastic fines are established they show that the theoretical crr vs1 correlations for silty sands with 5 to 15 nonplastic fines are all located to the far left of the semi empirical curves that separate liquefac

anisotropy of small strain stiffness in ticino sand comprehensive tests performed in a large calibration chamber and consisting of the propagation of seismic body waves in dry ticino silica sand are presented by virtue of the fact that both shear and constrained compression waves have been propagated in vertical horizontal and oblique directions five independent constants of the cross anisotropic elasticity model of the test have been established the tests have also made it possible to evaluate the influence of the structural inherent and stress induced anisotropy on the velocity of the propagated seismic body waves the influence of the principal effective stresses on the velocity of these waves is also described de nombreux essais realises dans une grande chambre d etalonnage et consistant en la propagation d ondes sismiques dans des sables siliceux et sec de ticino sont presentes les ondes de cisaillement et de compression ayant w emises dans des directions verticales horizontales et obliques les 5 constantes independantes du modele eastique

evaluation of the in situ state of fraser river sand les glissements de type coulee par liquefaction sont des phenomenes qui arrivent souvent dans le delta de la riviere fraser du cote de sand heads ces ruptures n ont pas trouve d explication et leurs causes restent du domaine de la speculation l etude d un tel glissement ayant eu lieu en 1985 dans la riviere fraser a proximite de sand heads a ete entreprise en utilisant les concepts d etats stationnaires pour qu un glissement par coulee impliquant la liquefaction de depots de sables puisse prendre place le sable doit presenter un ramollissement lors du cisaillement non draine et les contraintes de cisaillement en place doivent etre superieures a la resistance non drainee mobilisable on a effectue des essais de laboratoire sur des echantillons reconstitues de sable de la riviere fraser de facon a etablir les parametres d etat stationnaire les specimens de sol ont ete prepares par compaction humide et pluviation dans l eau des mesures de vitesse de propagation des ondes de cisaillement ont ete utilisees pour evaluer l etat en place des depots de sable recents et non cimentes on a trouve que l etat en place des depots recents au voisinage de sand heads se situait du cote l che de l etat stationnaire ce qui correspond aux instabilites observees sur le site

late archaean to early proterozoic granitoid magmatism and high grade metamorphism in the central limpopo belt south africa the central zone of the limpopo belt in southern africa has previously been interpreted as a segment of archaean crust which experienced its main deformation and metamorphism around 2 7 ga ago we report new single zircon u pb and pb pb ages for granitoid gneisses supracrustal rocks and anatectically derived granitic melt patches in the area around messina south africa the sand river gneiss is a composite suite of tonalitic to trondhjemitic rocks with protolith ages between 2 6 and 3 2 ga the singelele gneiss a heterogeneous granodioritic to quartz monzonitic rock has protolith ages between 2 55 and 2 58 ga since both the sand river and singelele gneisses experienced polyphase high strain ductile deformation this must have occurred later than 2 55 ga ago granulite facies pelitic gneisses of the beit bridge complex contain abundant spherical multifacetted zircons which reflect new zircon growth near or at the peak of metamorphism these zircons provide ages with a mean at 2026 5 6 3 ma which is interpreted as reflecting a high p t event 10 kbar 825 25 c granitic melt patches in the metapelites as well as in the sand river gneiss and anatectic granites are probably related to rapid near isothermal decompression to below 3 5 kbar and 600 750 c these rocks contain new magmatic zircons which yielded a mean age of 2005 6 4 4 ma and probably reflect a crustal melting event resulting from rehydration of the granulitic assemblage our zircon data support previous suggestions for only one single granulite facies event in the central zone and we suggest that this event occurred c 2027 ma ago since most of the deformation seen in the gneisses of the messina area must have occurred later than 2 55 ga ago it is likely that the limpopo orogeny at least in the central zone is not an archaean event but took place in the early proterozoic

liquefaction resistance of soils from shear wave velocity a simplified procedure using shear wave velocity measurements for evaluating the liquefaction resistance of soils is presented the procedure was developed in cooperation with industry researchers and practitioners and evolved from workshops in 1996 and 1998 it follows the general format of the seed idriss simplified procedure based on standard penetration test blow count and was developed using case history data from 26 earthquakes and 70 measurement sites in soils ranging from fine sand to sandy gravel with cobbles to profiles including silty clay layers liquefaction resistance curves were established by applying a modified relationship between the shear wave velocity and cyclic stress ratio for the constant average cyclic shear strain suggested by r dobry these curves correctly predicted moderate to high liquefaction potential for 95 of the liquefaction case histories and are shown to be consistent with the standard penetration test based curves in sandy soils a case study is provided to illustrate application of the procedure additional data are needed particularly from denser soil deposits shaken by stronger ground motions to further validate the simplified procedure

correlation between cyclic resistance and shear wave velocity for providence silts as an alternative to a field based liquefaction resistance approach cyclic triaxial tests with bender elements were used to develop a new correlation between cyclic resistance ratio crr and overburden stress corrected shear wave velocity vs1 for two nonplastic silts obtained from providence rhode island samples of natural nonplastic silt were recovered by block sampling and from geotechnical borings split spoon sampling the data show that the correlation is independent of the soils stress history as well as the method used to prepare the silt for cyclic testing the laboratory results indicate that using the existing field based crr vs1 correlations will significantly overestimate the cyclic resistance of the providence silts the strong dependency of the crr vs1 curves on soil type also suggests the necessity of developing silt specific liquefaction resistance curves from laboratory cyclic tests performed on reconstituted samples

behavior of a fine grained soil during the loma prieta earthquake results of an investigation into the behavior of a fine grained clayey soil at moss landing during the 1989 loma prieta earthquake are presented a deposit of this soil underlies portions of the mo

insight on seismic hazard studies for egypt abstract the seismic hazard studies for egypt have been initiated a long time ago aiming to predict the ground motion parameters at different geographical scales their review process had been routinely performed due to the increase of available instrumental observations rather than from methodological advances for the comprehensive understanding of the development of seismic hazard assessment sha studies in egypt we properly collect and test the existing sha maps computed at different geographic scales against the available observations data quality physical assumptions and adopted methodology most of these sha studies are probabilistic and the mapped ground motion acceleration values have been often largely exceeded by the observed values due to earthquakes occurred after their publication for each study we discuss and evaluate the input data methodology and the results obtained in order to understand the reasons behind the bad performance of the available seismic hazard maps and to avoid such shortcomings in future seismic hazard assessment finally we formulate suggestions that could be considered before new seismic hazard maps are released and then adopted for the real benefit of society

correlation between liquefaction resistance and shear wave velocity of granular soils a micromechanical perspective the shear wave velocity method has become an increasingly popular means to evaluate the liquefaction potential of granular soils understanding the fundamental mechanism underlying existing empiric

strength of undisturbed versus reconstituted silt and silty sand specimens the differences in undrained stress strain strength behavior between undisturbed and reconstituted silt and silty sand specimens tested at the same void ratio and initial stress state may be dramatic in all tests reported herein the undisturbed specimens showed dilative and ductile behavior whereas in all but a very few cases the accompanying reconstituted specimens at the same or lower density showed contraction much lower undrained strength and brittle behavior the test series included samples from a natural fluvial silt deposit as well as from silty sand hydraulically placed in a tailings dam when reconstituting specimens for laboratory testing it is not sufficient to only satisfy the criteria of correct density and grain size distribution but somehow the same fabric also must be reproduced otherwise deformation and stability analyses based on the results of reconstituted specimens or on in situ tests calibrated against such results may be misleading most of the reconstituted specimens

1 88 ga oxidized a type granites of the rio maria region eastern amazonian craton brazil positively anorogenic abstract 1 88 ga a type granites in the archean rio maria granite greenstone terrane of eastern amazonian craton brazil have much in common with the oxidized 1 4 ga anorogenic granites of the western united states nd isotopic data on these granites and their archean country rocks show that 1 the rio maria crust was differentiated from depleted mantle at 3 0 ga 2 the paleoproterozoic granites were derived from deep parts of this crust and 3 the paleoproterozoic granites postdate their protolith by at least 1 ga no convergent processes are known to have affected the eastern amazonian craton at 1 9 ga and therefore there is little doubt as to the anorogenic origin of the oxidized a type granites of rio maria recognition of this genuinely anorogenic proterozoic granite suite in amazonia adds cymatogenic flavor to the current debate on the origin of the mid proterozoic anorogenic granites of the western united states

geotechnical reconnaissance and liquefaction analyses of a liquefaction site with silty fine sand in southern taiwan article i nfo geotechnical reconnaissance of a recurrent liquefaction site at a quaternary alluvial deposit in southern taiwan was conducted to establish a comprehensive case history for liquefaction on silty fine sand with high fines content the liquefaction occurred at a silty fine sand layer with d50 0 09 mm and fines content greater than 35 and was triggered by a mw 6 4 earthquake on march 4 2010 which induced maximum horizontal acceleration up to 0 189 g at the site in situ subsurface characterizations including standard penetration test cone penetration test and shear wave velocity measurement were performed as well as cyclic simple shear tests on undisturbed specimens retrieved by a modified hydraulic piston sampler comparisons of cyclic re sistance ratios crrs indicate that cpt sounding with standard penetration rate could overestimate the re sistance ratio and drainage conditions during penetration should be considered for high fines content soil in the liquefaction analysis additionally variations of crrs from different in situ tests indicate that correlations among in situ tests and crr could be soil specific and precautions should be taken when using these curves on silty fine sands

assessment of the liquefaction susceptibility of fine grained soils observations from recent earthquakes and the results of cyclic tests indicate that the chinese criteria are not reliable for determining the liquefaction susceptibility of fine grained soils fine grained soils that liquefied during the 1994 northridge 1999 kocaeli and 1999 chi chi earthquakes often did not meet the clay size criterion of the chinese criteria cyclic testing of a wide range of soils found to liquefy in adapazari during the kocaeli earthquake confirmed that these fine grained soils were susceptible to liquefaction it is not the amount of clay size particles in the soil rather it is the amount and type of clay minerals in the soil that best indicate liquefaction susceptibility thus plasticity index pi is a better indicator of liquefaction susceptibility loose soils with pi 0 85 were susceptible to liquefaction and loose soils with 12 0 8 were systematically more resistant to liquefaction soils with pi 18 tested at low effective confining stresses

effects of gravel content on liquefaction resistance and its assessment considering deformation characteristics in gravel mixed sand many reports describe overestimation of liquefaction resistance based on sounding data related to ground materials containing coarse particles such as gravel and cobbles better methods of liquefac

liquefaction and flow failure during earthquakes two aspects of seismically induced liquefaction are discussed which are of vital engineering significance the triggering condition and the consequences of liquefaction the triggering condition is examined with respect to liquefaction analysis note being taken of the onset condition which is governed by cyclic strength consequences of liquefaction are discussed with respect to post seismic stability analysis in which the residual strength plays a major role procedures used for liquefaction analysis based on the results of in situ sounding tests are introduced and the applicability of this method for estimating associated ground settlements is discussed the evaluation of residual strength requires a better understanding of undrained sand behaviour results of extensive laboratory rests on japanese standard sand are examined and new index parameters are proposed to quantify undrained sand behaviour better the results of laboratory tests on silty sands are examined in the same way ah the results are

petrology of the chilliwack batholith north cascades washington generation of calc alkaline granitoids by melting of mafic lower crust with variable water fugacity calc alkaline granitoid rocks of the oligocene pliocene chilliwack batholith north cascades range from quartz diorites to granites 57 78 sio2 and are coeval with small gabbroic stocks modeling of major element trace element and isotopic data for granitoid and mafic rocks suggests that 1 the granitoids were derived from amphibolitic lower crust having ree rare earth element and sr nd isotopic characteristics of the exposed gabbros 2 lithologic diversity among the granitoids is primarily the result of variable water fugacity during melting the main effect of fh 2 o variation is to change the relative proportions of plagioclase and amphibole in the residuum the ree data for intermediate granitoids quartz diorite granodiorite eu eu 0 84 0 50 are modeled by melting with fh 2 o 1 kbar leaving a plagioclase pyroxene residuum in contrast data for leucocratic granitoids leuco granodiorites and granites eu eu 1 0 0 54 require residual amphibole in the source and are modeled by melting with fh 2 o 2 3 kbar consistent with this model isotopic data for the granitoids show no systematic variation with rock type 87sr 86sri 0 7033 0 7043 end 0 3 3 to 5 5 and overlap significantly with data for the gabbroic rocks 87sr 86sri 0 7034 0 7040 end 0 3 3 to 6 9 the fh 2 o variations during melting may reflect additions of h2o to the lower crust from crystallizing basaltic magmas having a range of h2o contents chillwack gabbros document the existence of such basalts one dimensional conductive heat transfer calculations indicate that underplating of basaltic magmas can provide the heat required for large scale melting of amphibolitic lower crust provided that ambient wallrock temperatures exceed 800 c based on lithologic and geochemical similarities this model may be applicable to other cordilleran batholiths

geochemistry zircon ages and whole rock nd isotopic systematics for palaeoproterozoic a type granitoids in the northern part of the delhi belt rajasthan nw india implications for late palaeoproterozoic crustal evolution of the aravalli craton determination of zircon ages as well as geochemical and sm nd isotope systematics of granitoids in the khetri copper belt of the aravalli mountains nw india constrain the late palaeoproterozoic crustal evolution of the aravalli craton the plutons are typical a type within plate granites derived from melts generated in an extensional tectonic environment they display ree and multi element patterns characterized by steep lree enriched and almost flat hree profiles and distinct negative anomalies for sr p and ti initial e nd values range from 1 3 to 6 2 and correspond to crustal sources with mean crustal residence ages of 2 5 to 2 1 ga a lower mafic crustal anatectic origin is envisaged for these granitoids and the heterogeneous e nd t values are inferred to have been acquired from the magma source region zircon pb pb evaporation and u pb ages indicate widespread rift related a type magmatism at 1711 1660 ma in the northern delhi belt and also suggest a discrete older magmatic event at around 1800 ma the emplacement ages of the compositionally distinct a type granitoid plutons and virtually coeval granulite metamorphism and exhumation in another segment of the aravalli mountains further signify that part of the aravalli crust evolved during a widespread extensional event in late palaeoproterozoic time

characterization of thick varved clayey silt deposits along the delaware river by field and laboratory tests the existence of thick compressible varved clayey silt deposits along the delaware river presents one major obstacle for design and construction of structures or industrial facilities in this region to understand the characteristics of this thick weak soil layer and then develop reliable soil parameters for future earthwork design and construction a comprehensive soil testing program was carried out the program consisted of both in situ tests e g standard penetration test borings piezocone penetration test cpt soundings marchetti flat dilatometer test soundings seismic shear wave test soundings cpt pore pressure dissipation tests and field vane shear tests and laboratory tests e g soil index tests consolidation tests triaxial tests and chemical tests additionally a field surcharge test program with and without installation of wick drains was carried out to investigate the compressibility of the thick clayey silt deposit and the efficiency of wick drains to help accelerate consolidation the field and laboratory test results showed that the varved clayey silt deposit was normally consolidated to slightly overconsolidated and moderately to highly compressible its physical properties were intermediate between those of savannah muddy clay and shanghai soft clay while much closer to that of shanghai soft clay due to its lamination structure in the horizontal direction the horizontal consolidation coefficient of the varved clayey silts was significantly greater than that in the vertical direction the measured undrained shear strength of the varved clay silt almost increased linearly with depth the installation of wick drains in the thick clayey silt deposits accelerated primary consolidation but showed no effect on the secondary consolidation under constant loading the findings obtained from this study will be beneficial for future design and construction of earthworks along the delaware river