荷载作用下软粘土土性指标变化规律试验研究

Experimental study on variation law of soil indexes of soft clay under load action

目前许多港口与海岸工程建设在深厚软粘土地基上,荷载作用下软粘土土性指标的变化成为工程设计中关心的问题,而固结度和上部结构物产生的竖向荷载是影响地基土体土性指标的主要因素。针对烟台港淤泥质粉质粘土原状土样,通过三轴固结不排水剪切试验,研究不同固结压力、不同固结度下软粘土抗剪强度和土性指标的变化规律。试验结果表明,荷载作用下软粘土的抗剪强度和土性指标基本随固结度和轴向偏应力的增大而线性增大,粘聚力增长幅度十分显著,而内摩擦角增长幅度相对较小。根据试验数据,提出工程设计中考虑荷载作用的土性指标计算公式。

Nowadays, many ports and coastal engineering projects have been constructed on the thick soft clay foundation. The variation of indexes of soft clay under load action becomes a problem which is further concerned in practical engineering design. However, the consolidation degree and the vertical load by upper structure are main factors affecting the indexes of foundation soil. Based on the undisturbed samples of mucky silty clay from Yantai Port, consolidated-undrained triaxial tests were carried out, then the variation laws of shear strength and indexes of soft clay under different consolidation pressures and different consolidation degrees were obtained. The results show that the shear strength and indexes of soft clay under load action almost present linear growth accompanied with the increase of consolidation degree and axial deviatoric stress. The increasing range of cohesion is quite obvious, while the increasing range of internal friction angle is relatively smaller. According to the experimental data, the calcula-tion formulas of soil indexes under load action were put forward which could be used in practical engineering design.