黏土Ⅰ型断裂韧度影响因素试验

Experimental study on factors of I-type fracture toughness of compacted clay

为研究击实黏土干密度、含水率对其断裂韧度的影响,把标准三点弯曲试验试样绕底部长边向前旋转90°,加载方向随之变为水平方向,使荷载的方向与重力方向垂直,从而消除自重对裂隙向土梁厚度、长度方向扩展的影响。对重庆地区罗系地层中的黏土岩风化形成的高塑限黏土进行了室内黏土Ⅰ型断裂韧度试验,总结了干密度、含水率对黏土断裂韧度的影响规律,结果表明,黏土Ⅰ型断裂韧度随其干密度的增大而增大,随其含水率的增大先增大后减小;存在一个最优含水率,此时断裂韧度取得最大值。

In order to investigate the effects of the dry bulk density and moisture content on the fracture toughness of compacted clay, a new method for the three-point bending test was used, in which the testing sample was rotated 90° in forward around its long side at the bottom, and the loading direction was thus turned to the horizontal direction, perpendicular to the direction of the gravity of the testing sample, so as to avoid the influence of its self-gravity on the fracture extending along the thickness and length of the soil beam. Laboratory tests on the I-type fracture toughness of high-plasticity compacted clay formed by rock weathering in the Jurassic formation in Chongqing City show that the fracture toughness of compacted clay increases with the dry bulk density, and that it increases first and then decreases with the increase of the moisture content, with an optimum moisture content existing, corresponding to the greatest fracture toughness.