李家坪隧道膨胀性围岩力学特性试验及塌方原因分析  

Experimental study on mechanical characteristics of Lijiaping tunnel expansive surrounding soils and analysis of tunnel collapse

作　　者：张毅[1,2] 折学森 高学伸[3] ZHANG Yi1,2 SHE Xuesen1, GAO Xueshen3(1. School of Highway, Chang＇an University, Xi＇an 710064, China;2. Henan Province Highway Management Center of Toll and Loan, Zhengzhou 450000, China ;3. Architects ＆ Engineers Co. , Ltd. of Southeast University, Nanjing 210096, China.)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]河南省收费还贷高速公路管理中心,河南郑州450000 [3]东南大学建筑设计研究院有限公司,江苏南京210096

出　　处：《水资源与水工程学报》2018年第1期203-208,共6页Journal of Water Resources and Water Engineering

基　　金：高等学校博士学科点专项科研基金项目(20110205110003)

摘　　要：为研究三淅高速公路李家坪隧道膨胀土软弱围岩性质,通过三轴强度试验和膨胀特性实验等室内试验研究了含水率、干密度对膨胀土三轴强度的影响。试验结果表明:含水率和干密度对膨胀土强度影响较大,对黏聚力的影响尤为显著,但在膨胀土的干密度较大时,干密度对内摩擦角的影响不明显。较小初始含水率的膨胀土吸水膨胀时将产生非常大的膨胀率和膨胀力,因此,工程上应对膨胀土区域采取防渗措施。此外,根据收敛约束法的理念推导了膨胀土围岩特征曲线,结果表明含水率的变化会使围岩压力发生很大变化。基于此,进一步分析了李家坪隧道塌方冒顶的原因,雨季施工造成膨胀土含水量增大,产生巨大的膨胀力,而支护体系薄弱,造成隧道冒顶塌方。In order to study the expansive soft rock properties of Li Jia Ping tunnel in San Xi highway,the impact of water content and dry density on expansive soil three-axis strength were investigated by three-axis strength test and expansion experiments. The test results showed that water content and dry density have a significant impact on the expansive soil strength,especially on the cohesion. However,the effects of dry density on the internal friction angle is not obvious when the dry density of the expansive soil is large. The expansive soil with small initial moisture content will produce very large expansion rate and expansive force when absorbing water and becoming expanded. Therefore,anti-seepage measures should be taken to the expansive soil area. In addition,according to the idea of convergence constraint method,the characteristic curve of surrounding rock of expansive soil is deduced. The structure shows that the change of water content will cause great change of surrounding rock pressure. Based on this,further analysis of the cause of roof collapse was analyzed. Constructing during the rainy season increased the water content of expansive soil,the poor support can not resist the enormous expansive force. As a result,the roof collapsed.

关 键 词：膨胀土 软弱围岩 三轴强度试验 膨胀试验 力学特性 隧道塌方原因 

分 类 号：TV223.1[水利工程—水工结构工程] TU45[建筑科学—岩土工程]