红层软岩膨胀力学特性试验研究  

Experimental study on expansive mechanical characteristics of red-bed soft rock

作　　者：和铭 魏良帅 贾逸[1,2] 黄安邦[1,2] 王家柱 黄细超 HE Ming;WEI Liangshuai;JIA Yi;HUANG Anbang;WANG Jiazhu;HUANG Xichao(Institute of Exploration Technology, Chinese Academy of Geological Sciences, Chengdu611734, Sichuan, China;Technical Center for Geological Hazard Prevention and Control, China Geological Survey, Chengdu611734, Sichuan, China;Chengdu Center of Geological Survey, China Geological Survey, Chengdu610081, Sichuan, China;State Key Laboratoryof Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu610059, Sichuan, China)

机构地区：[1]中国地质科学院探矿工艺研究所,四川成都611734 [2]中国地质调查局地质灾害防治技术中心,四川成都611734 [3]中国地质调查局成都地质调查中心,四川成都610081 [4]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059

出　　处：《水利水电技术》2019年第4期171-178,共8页Water Resources and Hydropower Engineering

基　　金：中国地质调查局二级项目(DD20160287);国家自然科学基金项目(41372306)

摘　　要：红层地区岩体膨胀变形现象显著。为研究红层软岩膨胀力学性能,采用YYP-50型岩石膨胀压力试验仪和岩石自由膨胀率试验仪对某隧洞区5种不同岩性的红层软岩进行室内膨胀特性试验,并通过pH计测定了膨胀压力试验前后水溶液的pH值。试验结果表明:该隧洞区5种红层软岩的平均膨胀压力差异明显,最低为175.13 kPa,最高可达2 080.16 kPa,膨胀力的对数与膨胀应变呈线性增长关系,膨胀压力与干密度、吸水率皆呈正相关,与初始含水率呈负相关;膨胀压力试验后5种软岩的水溶液pH值均大于7,且不同地层水溶液pH值变化率不同,膨胀压力的大小与pH值及其变化率呈正相关;5种软岩的平均自由膨胀率相对较大,纵向、径向最高可达40.8%和32.4%,平均膨胀压力与平均自由膨胀率表现出指数增长趋势。研究成果可为今后膨胀岩地区工程建设提供一定的理论支撑。The phenomenon of expansive deformation of rock mass in red bed area is obvious. In order to study the expansive mechanical properties of red-bed soft rock, the indoor experiments on the expansive characteristics of five kinds of red-bed soft rock with different lithologies within the area of a tunnel are carried out with YYP-50 rock expansion pressure tester and rock free expansion test instrument, and then the pH values of aqueous solution before and after expansion pressure test are measured with pH meter as well. The experiment shows that the differences of the mean expansion pressure among five kinds of red-bed soft rocks within that tunnel area are obvious, of which the lowest is 175.13 kPa and the highest is up to 2 080.16 kPa, while the logarithm of expansion force exhibits a linear increase relationship with the expansive stress, for which the expansive pressure is positively correlated to both the dry density and the water absorption ratio and is negatively correlated with initial water content. All the aqueous solution pH values of the five kinds of soft rocks after the expansive pressure experiment are larger than 7, while the aqueous solution pH values in different strata are different as well, for which the magnitude of expansive pressure is positively correlated to the pH value and its changing rate. The mean free expansive rates of the five kinds of soft rocks are relatively larger, of which the maximums to the longitudinal direction and radial direction can reach to 40.8% and 32.4% respectively, while the mean expansion pressure and the mean free expansive rate exhibit exponential increase trends. This study result can provide a certain theoretical support for the construction carried out within expansive rock region in the days to come.

关 键 词：引水隧洞 红层软岩隧道 膨胀 黏土矿物 pH值 隧道围岩大变形 岩体膨胀性分级 陆相碎屑深积地层 

分 类 号：TU45[建筑科学—岩土工程]