上海软土小应变三轴试验及本构模拟  

Small-strain triaxial tests and constitutive modeling of Shanghai soft clays

作　　者：杨同帅 叶冠林[1] 顾琳琳[2] YANG Tong-shuai;YE Guan-lin;GU Lin-lin(Department of Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Department of Civil Engineering,Qingdao University of Technology,Qingdao 266033,China)

机构地区：[1]上海交通大学土木工程系,上海200240 [2]青岛理工大学土木工程学院,山东青岛266033

出　　处：《岩土工程学报》2018年第10期1930-1935,共6页Chinese Journal of Geotechnical Engineering

摘　　要：软土地区新建地下工程为了减少对周边的影响,周边土体的变形通常要求控制在小应变范围内（0.001%-0.1%）。近年来随着环境要求的不断提高,软土在小应变范围内的力学特性日益受到关注。目前国内在三轴试验中测量软土小应变力学特性的研究相对较少,也缺乏相应的试验数据。利用安装有LVDT局部位移传感器的三轴仪,对上海（2）-（6）层软土进行了K0固结不排水剪切试验,成功获得了上海软土从0.001%小应变到20%大应变范围内的剪切模量变化规律。通过分别用初始剪切模量和有效平均主应力来对剪切模量进行归一化处理,揭示了上海软土的非线性特征、土体剪切模量的衰减规律等。考虑土体应力状态、孔隙比和超固结比的经验公式能够合理地描述上海软土层初始剪切模量;经典的骨干曲线模型能较好地拟合各土层的剪切模量衰减规律。In order to reduces the influence of the existing buildings in the surrounding area, the surrounding soil of the new project usually requires the control of the small strain state（0.001%-0.1%）. In recent years, the construction scale of underground projects has been continuously expanded, and the mechanical properties of soft clay in the small strain range have received increasing attention. At present, the study on the small-strain mechanical properties of soft soils in triaxial tests is relatively few and lack of the relevant test data. A small strain is developed based on an the LVDT sensors with high-accuracy triaxial apparatus, and K0 consolidation undrained shear tests on layer（2）-（6） soils are performed of Shanghai soft using the triaxial apparatus. The change of modulus of Shanghai soft soils in the small strain range of 0.001%-20% is obtaived. The shear modulus is normalized by using the initial shear modulus and effective average principal stress, so as to reveal the nonlinear characteristics of Shanghai soft soils as well as the shear stiffness attenuation characteristics with strain, etc. The empirical formula considering stress state, pore ratio and overconsolidation ratio of soils can reasonably describe the initial shear modulus of Shanghai soft soils. The classical model for backbone curve can better fit the attenuation rules of shear modulus of each soil layer.

关 键 词：小应变 软土 剪切模量 三轴试验 本构模型 

分 类 号：TU43[建筑科学—岩土工程]