主应力轴旋转下(b=0.5)原状软黏土孔压特性  

CHARACTERISTICS OF PORE WATER PRESSURE OF INTACT SOFT CLAY UNDER ROTATION OF PRINCIPAL STRESS AXES AND INTERMEDIATE PRINCIPAL STRESS COEFFICIENT(b) OF 0.5

作　　者：温晓贵[1] 郑鸿镔[1] 周建[1] 张勋[1] 

机构地区：[1]浙江大学软弱土与环境土工教育部重点实验室,浙江杭州310058

出　　处：《岩石力学与工程学报》2010年第12期2558-2565,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(50778162);浙江省回国留学基金项目(J20090026);浙江大学中央高校基本科研业务费专项资金项目(1A4000-172210127)

摘　　要：采用浙江大学空心圆柱扭剪仪(ZJU-HCA),对杭州原状软黏土进行固结不排水主应力轴旋转试验,探讨剪应力变化、初始剪应力水平高低及主应力轴正向和逆向旋转对黏土孔隙水压力(简称孔压)发展的影响。试验中保持平均主应力不变,中主应力系数b=0.5。试验结果表明:定向剪切产生的孔压主要受剪应力控制;用双重屈服面理论得到孔压系数,结合孔压线性拟合结果发现,若初始剪应力低于峰值剪应力,体积屈服面函数不受主应力轴旋转影响;若初始剪应力接近峰值剪应力,主应力轴开始旋转时的孔压上升速率相对较高,但后期孔压反而会下降;纯主应力轴旋转过程中的孔压上升速率主要受初始剪应力大小控制。主应力轴正向旋转较逆向旋转产生的孔压小;主应力轴逆向旋转相对正向旋转对整个剪切过程的孔压发展有较大影响。Consolidated-undrained shear tests of rotation of principal stress axes are carried out on Hangzhou intact soft clay with hollow cylinder torsion shear apparatus（ZJU-HCA）.The influence of shear stress change,initial shear stress level and both positive and inverse rotation of principal stress axes on characteristics of pore water pressure development clay are discussed.In the tests,the mean principal stress is kept constant and the intermediate principal stress coefficient is set to 0.5.The test results show that the pore water pressure in fixed shear period is mainly controlled by shear stress.The pore water pressure coefficient is acquired by double yield surface theory,which is combined with linear fitting results of pore water pressure to reveal that the volume yield surface function is not affected by the rotation of principal stress axes when initial shear stress is below the peak shear stress.If the initial shear stress is close to the peak shear stress,a relatively high velocity of pore water pressure is generated at the beginning of rotation,but later pore water pressure decreases.The corresponding velocity of pore water pressure in the rotation process of pure principal stress axes is mainly dominated by initial shear stress.The pore water pressure under positive rotation of principal stress axes is smaller than that under inverse rotation.The influence of inverse rotation of principal stress axes on pore water pressure is larger than that of positive rotation through the whole shearing process.

关 键 词：土力学 主应力轴旋转 中主应力系数 剪应力 孔隙水压力 软黏土 

分 类 号：TU43[建筑科学—岩土工程]