基于线弹性力学的非饱和红粘土裂缝开展分析

Analysis of crack development of unsaturated red clay based on linear elasticity mechanics

湖南郴宁高速公路沿线分布的红粘土是一种典型的高塑性粘土,极易干燥失水开裂导致严重的工程病害。以郴宁高速公路红粘土为研究对象,分析了粘土干缩裂缝的开展机理,采用线弹性力学和非饱和土力学理论,在一定的假设条件下导出了考虑土体抗拉强度的裂缝开展深度的理论解。理论解分析表明,裂缝开展深度主要受地表基质吸力控制,地表基质吸力越大,裂缝越深;当吸力梯度较小时,吸力梯度对裂缝深度的影响较大;土体参数泊松比对裂缝开展深度的影响较小。

The red clay distributed along the Chen-Ning Expressway in Hunan Province is a typical high-plasticity clay, which is readily to dry and crack and cause serious engineering diseases. With the red clay of Chen-Ning Expressway as an object of study, the mechanism of clay shrinkage crack was analyzed herein. Based on the linear elastic and unsaturated soil mechanics theories, certain assumptions and with the tensile strength of the soil in mind, a theoretical solution of the crack depth was derived. Analysis of the theoretical solution shows that, the depth of the crack development is mainly controlled by the surface matrix suction. The greater the surface matric suction, the deeper the cracks; crack depth is greatly influenced by the suction gradient when the suction gradient is small; crack depth development is less influenced by the Poisson ratio.