Soil liquefaction, and the permanent deformations that frequently result from it, have caused significant damage in past earthquakes. The procedures used in contemporary geotechnical earthquake engineering practice ar...Soil liquefaction, and the permanent deformations that frequently result from it, have caused significant damage in past earthquakes. The procedures used in contemporary geotechnical earthquake engineering practice are generally based on simplified procedures for the evaluation of the liquefaction potential. The work describes a framework for performance-based earthquake engineering and its use in the development of a performance-based procedure for liquefaction hazard evaluation. The performance-based procedure will be used to show how consistent application of conventional procedures for evaluation of liquefaction potential can influence performance prediction. Implications for liquefaction-resistant design will also be discussed. The purpose is to summarize current procedures for practical prediction of liquefaction behavior, to describe recent advances in the understanding of liquefaction behavior, and to describe the incorporation of this improved understanding into new solutions for detailed modeling of soil liquefaction, Simplified procedures for evaluation of liquefaction hazards will be reviewed relatively briefly, with more details devoted to emerging knowledge about the mechanics of liquefiable soil behavior, and methods for incorporating those mechanics into improved models for performance prediction. In particular it focuses about the influence on the evaluation of Cyclic Resistance Ratio （CRR） by different in-situ tests （Cone Penetration Test （CPT）. Standard Penetration Test （SPT） and Seismic Dilatometer Marchetti Test （SDMT）） and by different shear waves velocity measurements （Down Hole D-H. Cross Hole C-H, Seismic Dilatometer Marchetti Test SDMT）.展开更多
The characteristics of residual soils are very different from those of sedimentary soils.Although the strength characteristics of sedimentary soils have been studied extensively,the shear strength characteristics of g...The characteristics of residual soils are very different from those of sedimentary soils.Although the strength characteristics of sedimentary soils have been studied extensively,the shear strength characteristics of granitic residual soils(GRS)subjected to the weathering of parent rocks have rarely been investigated.In this study,the shear strength characteristics of GRS in the Taishan area of southeast China(TSGRS)were studied by field and laboratory tests.The field tests consisted of a cone penetration test(CPT),borehole shear test(BST),self-boring pressuremeter test(SBPT),and seismic dilatometer Marchetti test(SDMT).The shortcomings of laboratory testing are obvious,with potential disturbances arising through the sampling,transportation,and preparation of soil samples.Due to the special structure of GRS samples and the ease of disturbance,the results obtained from laboratory tests were generally lower than those obtained from situ tests.The CPT and scanning electron microscopy(SEM)results indicated significant weathering and crustal hardening in the shallow TSGRS.This resulted in significant differences in the strength and strength parameters of shallow soil obtained by the BST.Based on the SDMT and SBPT results,a comprehensive evaluation method of shear strength for TSGRS was proposed.The SBPT was suitable for evaluating the strength of shallow GRS.The material index(ID)and horizontal stress index(KD)values obtained by the SDMT satisfied the empirical relationship proposed by Marchetti based on the ID index,and were therefore considered suitable for the evaluation of the shear strength of deep GRS.展开更多
This paper aims to deal with the comparison of the estimated settlements derived by in situ tests with the observed settlements in site, in order to evaluate the accuracy of settlement prediction by in situ tests, in ...This paper aims to deal with the comparison of the estimated settlements derived by in situ tests with the observed settlements in site, in order to evaluate the accuracy of settlement prediction by in situ tests, in comparison not only with site observation by topographic means, but also with the values of settlements derived by numerical analysis by means of PLAXIS 2D and 3 D. The site where are carried out the tests and periodically are observed the settlements since the beginning of construction process, is located in the Oil Product Terminal, at the industrial park of Porto Romano, Durres, Albania. The main purpose of this project was the ground improvement by using preloading method in order to prevent liquefaction process and settlements. The data used to conduct this study are taken by the site investigation done after inserting into the soil vertical drains made of columns of free--draining gravel （gravel pile drains） until 14 m depth and center-to-center spacing of 2 m, and wick drains （premanufactured） until 25 m depth and center-to-center spacing of 1.8 m. The observed settlements are periodically measured by topographic equipments. This paper will present the conclusions derived by settlement analyzes from in situ tests and site observations.展开更多
文摘Soil liquefaction, and the permanent deformations that frequently result from it, have caused significant damage in past earthquakes. The procedures used in contemporary geotechnical earthquake engineering practice are generally based on simplified procedures for the evaluation of the liquefaction potential. The work describes a framework for performance-based earthquake engineering and its use in the development of a performance-based procedure for liquefaction hazard evaluation. The performance-based procedure will be used to show how consistent application of conventional procedures for evaluation of liquefaction potential can influence performance prediction. Implications for liquefaction-resistant design will also be discussed. The purpose is to summarize current procedures for practical prediction of liquefaction behavior, to describe recent advances in the understanding of liquefaction behavior, and to describe the incorporation of this improved understanding into new solutions for detailed modeling of soil liquefaction, Simplified procedures for evaluation of liquefaction hazards will be reviewed relatively briefly, with more details devoted to emerging knowledge about the mechanics of liquefiable soil behavior, and methods for incorporating those mechanics into improved models for performance prediction. In particular it focuses about the influence on the evaluation of Cyclic Resistance Ratio （CRR） by different in-situ tests （Cone Penetration Test （CPT）. Standard Penetration Test （SPT） and Seismic Dilatometer Marchetti Test （SDMT）） and by different shear waves velocity measurements （Down Hole D-H. Cross Hole C-H, Seismic Dilatometer Marchetti Test SDMT）.
基金the funding support from the National Natural Science Foundation of China(Grant No.51709290)the Key Scientific Research Project of colleges and universities in Henan Province-Special Project of Basic Research(Grant No.20zx009)the Key Research Projects of Higher Education Institutions in Henan Province(Grant No.22A580008).
文摘The characteristics of residual soils are very different from those of sedimentary soils.Although the strength characteristics of sedimentary soils have been studied extensively,the shear strength characteristics of granitic residual soils(GRS)subjected to the weathering of parent rocks have rarely been investigated.In this study,the shear strength characteristics of GRS in the Taishan area of southeast China(TSGRS)were studied by field and laboratory tests.The field tests consisted of a cone penetration test(CPT),borehole shear test(BST),self-boring pressuremeter test(SBPT),and seismic dilatometer Marchetti test(SDMT).The shortcomings of laboratory testing are obvious,with potential disturbances arising through the sampling,transportation,and preparation of soil samples.Due to the special structure of GRS samples and the ease of disturbance,the results obtained from laboratory tests were generally lower than those obtained from situ tests.The CPT and scanning electron microscopy(SEM)results indicated significant weathering and crustal hardening in the shallow TSGRS.This resulted in significant differences in the strength and strength parameters of shallow soil obtained by the BST.Based on the SDMT and SBPT results,a comprehensive evaluation method of shear strength for TSGRS was proposed.The SBPT was suitable for evaluating the strength of shallow GRS.The material index(ID)and horizontal stress index(KD)values obtained by the SDMT satisfied the empirical relationship proposed by Marchetti based on the ID index,and were therefore considered suitable for the evaluation of the shear strength of deep GRS.
文摘This paper aims to deal with the comparison of the estimated settlements derived by in situ tests with the observed settlements in site, in order to evaluate the accuracy of settlement prediction by in situ tests, in comparison not only with site observation by topographic means, but also with the values of settlements derived by numerical analysis by means of PLAXIS 2D and 3 D. The site where are carried out the tests and periodically are observed the settlements since the beginning of construction process, is located in the Oil Product Terminal, at the industrial park of Porto Romano, Durres, Albania. The main purpose of this project was the ground improvement by using preloading method in order to prevent liquefaction process and settlements. The data used to conduct this study are taken by the site investigation done after inserting into the soil vertical drains made of columns of free--draining gravel （gravel pile drains） until 14 m depth and center-to-center spacing of 2 m, and wick drains （premanufactured） until 25 m depth and center-to-center spacing of 1.8 m. The observed settlements are periodically measured by topographic equipments. This paper will present the conclusions derived by settlement analyzes from in situ tests and site observations.
