某水电站坝址区河床覆盖层物理力学特性及其参数取值分析

Physical and Mechanical Characteristics of Riverbed Overburden in a Dam Site and Parameter Selection Analysis

以四川大渡河某水电站工程坝址地质勘察为背景,统计坝址区河床覆盖层物理力学参数,从试验方法和合理性2个方面探讨物理力学参数取值方法。结果表明,试验方法对河床覆盖层物理力学参数影响较大,试验探究时应选择贴近实际的试验材料和仪器;不同的取值方法导致所得的参数离散性较大,为保证参数的合理性,需进行大量的对比分析;初步判断,河床覆盖层物理力学性状较好,可修建100 m级大型土石坝,但存在坝基渗漏、坝基沉降、渗流破坏等工程地质问题。研究成果为该工程后期设计提供可靠的物理力学参数,也可为类似地区地质勘察提供参考。

Taking the geological survey of the dam site of a hydropower station on the Dadu River in Sichuan as the background,the physical and mechanical parameters of the riverbed overburden in the dam site area are counted,and the method of determining the physical and mechanical parameters is discussed from two aspects of test method and rationality.The results show that,(a)the test method has a great influence on the physical and mechanical parameters of the riverbed overburden,and the test materials and instruments close to the actual situation should be selected when the test is explored;(b)different value selection methods lead to greater dispersion of the parameters obtained,and in order to ensure the rationality of the parameters,a lot of comparative analysis is required;and(c)it is preliminarily judged that the physical and mechanical properties of the riverbed overburden are good,and a 100 m-level large earth-rock dam can be built,but there are engineering geological problems such as dam foundation leakage,dam foundation settlement and seepage damage.The research results will provide reliable physical and mechanical parameters for the later design of the project,and also provide references for the geological surveys in similar areas.