含水率对煤系土抗剪强度的影响  

Influence of water contents on shear strength of coal-bearing soil

作　　者：胡昕[1,2] 洪宝宁[2] 杜强[2] 孟云梅[3] 

机构地区：[1]中国电力工程顾问集团西北电力设计院,西安710065 [2]河海大学岩土力学与堤防工程教育部重点实验室,南京210098 [3]南京工程学院建筑工程学院,南京211167

出　　处：《岩土力学》2009年第8期2291-2294,共4页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.50279008);广东省交通厅科技项目(No.2002-06)

摘　　要：煤系土具有遇水软化的特点,强度随含水率的增加急剧下降。以分布在广州-梧州高速公路沿线的煤系土为研究对象,在分析其物理特性的基础上,通过常规直接剪切试验测定了不同含水状态煤系土试样的抗剪强度,分析了含水率对煤系土抗剪强度的影响,并提出了实际工程中处治煤系土的建议。研究结果表明:煤系土抗剪强度与起始含水率具有明显的相关关系,且起始含水率越大,抗剪强度越小。随着含水率的增大,煤系土黏聚力总体呈减小趋势,但变化趋势具有显著的阶段性。当含水率小于某一值时,煤系土黏聚力随含水率增大变化幅度较小;当含水率高于该值后,煤系土黏聚力随含水率增大急剧降低,凝聚力对数与含水率呈线性关系。含水率变化对煤系土内摩擦角的影响较小,但在含水率增大过程中,煤系土内摩擦角先增后减,具有明显的峰值。Coal-bearing soil is weakened when encountering water and its strength is sharply dropped down with increasing water content. Taking coal-bearing soil which ranges along with Guang-Wu Expressway for example, and based on analyzing the physical properties of coal-beating soil, its shear strength is measured through direct shear test; influence of water contents on shear strength of coal-bearing soil is analyzed; and some suggestions are put forward to treat coil-bearing soil. The results indicate that the shear strength and initial water content of coal-bearing soil have marked correlationship; and the bigger initial water content of coal-beating soil is, the smaller its shear strength is. With water content increasing, cohesion of coal-bearing soil decreases overall; but its changing trend is of marked characteristic of stage, When water content of coal-bearing soil is under some value, its cohesion changes in small ranges; after water content of coal-bearing soil is over the value, its cohesion decreases with water content increasing; and the interrelationship between the logarithm of its cohesion and water content is linear. Water content of coal-bearing soil has no marked effect on its internal friction angle; but its internal friction angle firstly increases and then decreases, so it has marked peak value.

关 键 词：煤系土 抗剪强度 水敏感性 直剪试验 

分 类 号：TU411.7[建筑科学—岩土工程] TU443[建筑科学—土工工程]