摘要
基于结构性土易受扰动的特点,在典型花岗岩残积土地层上开展自钻旁压试验(SBPT)和地震扁铲试验(SDMT),以此提出获取原位剪切模量-剪应变(G-γ)衰减曲线的建议方法。为了分析建议方法的适宜性,开展共振柱试验(RCT)获得常规的室内G-γ衰减曲线,同时结合RCT与SDMT数据推求近似原位G-γ曲线。结果表明,利用SBPT与SDMT可以直接获得完整的土体原位G-γ衰减曲线,采用Stokeo模型能很好地描述该曲线;基于对比分析,发现在相同应力条件下室内试验的剪切模量低于原位试验值,证明取样、运输和制样等扰动因素对花岗岩残积土造成不可恢复的结构损伤;用RCT结合SDMT结果拟合得到的近似原位G-γ曲线的初始阶段与建议方法一致,但曲线衰减速率明显偏高。综合比较3种方法,认为建议方法在残积土以及其他结构性土体的刚度分析中具有更好的适宜性,可为相关工程参数的选取提供参考。
The self-boring pressure meter tests(SBPT) and seismic dilatometer tests(SDMT) are conducted in the granite residual soil to obtain the in-situ shear modulus and shear modulus degradation. The shear modulus decay by shear strain was measured by resonant column tests(RCT), and the approximate in-situ shear modulus decay curves were deduced from the data of RCT and SDMT to analyze the suitability of the proposed approach. The results show that complete in-situ shear modulus degradation curves can be directly derived using‘Stokeo model’ from the combination of initial shear modulus G0 measured by SDMT and G-γ decay curve measured by SBPT. By comparing the results of resonant column tests under different stress states, a deduction is found in laboratory process of sampling, transporting and preparing of soil, causing unrecoverable damage in the soil. By comparing the results of the forecasting method by RCT and SDMT, the initial stage of the G-γ decay curves are found consistent with the proposed method. However, the stiffness attenuation rates of the proposed method are lower. After a comprehensive comparison of the three methods, the proposed approach proved to show a good suitability in the stiffness analysis of structural soil. The result provides an important reference for the selection of engineering parameters in relative soil layers.
作者
安然
孔令伟
黎澄生
郭爱国
AN Ran;KONG Ling-wei;LI Cheng-sheng;GUO Ai-guo(State Key Laboratory of Geomechanics and Geotechnlcal Engineenng,Institute of Rock and Soil Mechanics Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beljing 100049,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2018年第12期4429-4436,共8页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.11672320)~~
关键词
花岗岩残积土
G-γ衰减曲线
自钻旁压
地震扁铲侧胀
适宜性
granite residual soil
G-γdecay curves
self-boring pressure meter test
seismic dilatometer test
suitability
