基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。

Model Test on the Physical Property of Riverbed Sand-Gravel Layer of Dam Foundation

The objective of the study is to investigate the physical properties of deep overburden layer with less expense and more reliability. We took the riverbed sand-gravel layer of the dam foundation at Shuangjiangkou hydropower station on Dadu river as case study, and carried out large-scale indoor model tests to research the variation regularities of pressuremeter modulus and  blow count of dynamic test against density, gradation, and overburden pressure. According to indoor model test results and in-situ pressuremeter tests and borehole tests, we deduced the density of sand-gravel in the dam foundation area, based on which we conducted indoor triaxial test and seepage test to acquire the basic mechanical parameters and seepage parameters. It was revealed that the pressuremeter modulus and the blow count of dynamic test were in positive relation with density, gradation, and overburden layer. The research results provide a new approach of testing the physical properties of deep overburden layer.