干湿循环作用下泥质红砂岩软化及崩解特性试验研究  

Experimental study on softening and slake characteristics of red silty sandstone under drying-wetting cycles

作　　者：张艳林 王聪 汤禧龙 吴远达 Zhang Yanlin;Wang Cong;Tang Xilong;Wu Yuanda(Sinohydro Bureau 7 Co.,Ltd.,Chengdu 610081,China;School of Civil Engineering,Wuhan University,Wuhan 430072,China)

机构地区：[1]中国水利水电第七工程局有限公司,成都610081 [2]武汉大学土木建筑工程学院,武汉430072

出　　处：《工程勘察》2024年第1期14-19,共6页Geotechnical Investigation & Surveying

基　　金：国家自然科学基金(41772308).

摘　　要：在我国华南地区广泛分布的新近系地层中,岩体的工程性质较差,季节性降雨后易出现大变形破坏。为揭示该地层岩石特殊的水理特性,以典型的宿迁组红砂岩为研究对象,首先对其耐久性和软化性进行测定,然后开展了干湿循环试验和循环后试样的力学特性试验,最后通过核磁共振技术对干湿循环过程中试样的孔隙特征进行检测,分析其力学性能的劣化机理。试验结果表明:红砂岩吸水软化特征明显,但耐久性好,软化系数ω=0.75,二次崩解指数I_(d2)=0.96;干湿循环过程中试样的强度不断降低,干湿循环10次后的单轴抗压强度为饱和状态下的52.3%;干湿循环过程中红砂岩内部产生了大量的微裂隙,孔隙率增加也较为明显,胶结结构的破坏是导致干湿循环过程中红砂岩强度不断降低的主要原因。The Neogene strata is widely distributed in South China,which engineering properties of rock mass are relatively poor,and large deformation and failure are easy to occur after seasonal rainfall.In order to understand the water physical properties of the rock in Neogene strata,an experimental study was carried out on the typical Suqian formation red silty sandstone samples.Firstly,its durability and watersoftening characteristics were measured,and then the drying-wetting cycle tests and corresponding uniaxial tests were carried out,finally the pore characteristics of the sample during the drying-wetting cycles were determined by nuclear magnetic resonance(NMR)method,meanwhile the deterioration mechanism of its mechanical properties was analyzed.The test results show that the strength of red sandstone decreases after water saturation,and the water-softening coefficient is 0.75.The red sandstone has good durability,and the secondary disintegration index I_(d2)is 0.96.The strength of the sample decreases continuously with the increase of drying-wetting cycles,and the uniaxial compressive strength after ten times of drying-wetting cycles is 52.3%of that in the saturated state.During the drying-wetting process,a large number of micro fractures are produced in the samples,and the incensement of porosity is also obvious.The destruction of cemented structures is the main reason for the continuous reduction of the strength of this red sandstone during the drying-wetting process.

关 键 词：干湿循环 软化性 耐崩解性 T_(2)谱 

分 类 号：TU452[建筑科学—岩土工程]