摘要
结合细粒土室内直剪试验,并在剪切试验下研究了不同的粗粒含量(0%、20%、40%、60%)、不同含水率(12%、18%、20%)以及不同厚度(2、5、8mm)的软弱夹层土抗剪强度参数特性。试验结果表明,室内常规直剪试验测得的软弱夹层土的粘聚力C偏高,内摩擦角φ偏低,常规小直剪测得的综合摩擦系数f值高于软弱夹层土在岩块中的表现。便携式直剪的剪切强度随含水率增加逐渐降低,小直剪的剪切强度随含水率的增加先增大后减小,中间界限含水率值为18%;两种试验方法对粘聚力的影响规律是不同的,含水率的增加使内摩擦角发生不同程度的降低。在相同的法向应力下,随着厚度的增加,剪切强度呈现不同程度的降低;并随着厚度的增加,摩擦系数f大体呈逐渐减小趋势,当厚度超过一定值(大概8mm)后,摩擦系数f趋于稳定随着粗粒含量的增加,剪应力大体都呈现逐渐下降的趋势,在较大法向应力下,剪应力值趋于稳定。
Combined with the indoor direct shear test of fine-grained soil,this study investigates characteristics of shear strength parameters of the weak interlayer soil at different gravel content(0%,20%,40%and 80%)and water content(12%,18%and 20%)and thickness(2mm,5mm and 8mm)by direct shear test of weak interlayer soil.The results indicate that the cohesive force C of the weak interlayer soil measured by the conventional direct shear test is higher,and the internal friction angle is lower,and the comprehensive friction coefficient f measured by the conventional small straight shear is higher than that of the weak interlayer in the performance.The shear strength of the portable straight shear decreases gradually with the increase of the water content,while the shear strength of the small straight shear increases first and then decreases with the increase of the water content,and the water content in the middle boundary is 18%.It can be seen that the influence of the two test methods on the cohesion is different.The increase of the water content causes the internal friction angle to be reduced to different degrees.Under the same normal stress,the shear strength decreases with the increase of the thickness.With the increase of the thickness,the friction coefficient f gradually decreases gradually.When the thickness exceeds the certain value(about 8mm),the friction coefficient f tends to be stable.With the increase of coarse grain content,the shear stress tends to decrease gradually,especially under the large normal stress,the shear stress value tends to be stable.
作者
许飞
滕伟福
李恒
XU Fei;TENG Weifu;LI Heng(Faculty of Engi.,China Univ.of Geosciences,Wuhan 430074,China;Three Gorges Research Center for Geo-hazard of Ministry of Education,China Univ.of Geosciences,Wuhan 430074,China)
出处
《低温建筑技术》
2018年第6期107-111,共5页
Low Temperature Architecture Technology
关键词
夹层土
结构面
直剪试验
抗剪强度
weak interlayer soil
structural plane
direct shear
shear strength
