浸水过程中黄土孔隙气压特性的现场浸水试验研究  

Properties of Pore Air Pressure in Loess During Soaking:Insights from Field Immersion Test

作　　者：曲晨飞[1] 杨庆义[1] 刘荣豪 程洋 纪成亮[1] 李仁杰[1] 张继超 姚志华[3] 张登飞 QU Chenfei;YANG Qingyi;LIU Ronghao;CHENG Yang;JI Chengliang;LI Renjie;ZHANG Jichao;YAO Zhihua;ZHANG Dengfei(Survey Division,Shandong Electric Power Engineering Consulting Institute Co.,Ltd.,Jinan 250013,Shandong,China;State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an 710069,Shaanxi,China;Department of Airdrome Construction Engineering,Air Force Engineering University,Xi’an 710038,Shaanxi,China)

机构地区：[1]山东电力工程咨询院有限公司勘测事业部,山东济南250013 [2]西北大学地质学系,大陆动力学国家重点实验室,陕西西安710069 [3]空军工程大学机场建筑工程系,陕西西安710038

出　　处：《西北地质》2025年第2期146-158,共13页Northwestern Geology

基　　金：国家自然科学基金项目“增湿-振动下非饱和黄土的渗透和剪切特性及其堑坡失稳机理研究”(42372324),“增湿-剪切耦合作用下非饱和滑带黄土的劣化机制研究”(41907233)联合资助。

摘　　要：在黄河流域的黄土高原,黄土灾害频发,其关键的地质基因在于对水极为敏感。其中黄土场地遇水后的湿陷变形的科学评价,是黄土灾害研究的主题之一。黄土场地湿陷性逐渐由“最大湿陷势”向“可能湿陷势”转变,迫切需要查明现场试坑浸水试验过程中,黄土中水分入渗-气体迁移-湿陷变形的多场耦合过程。目前,有关现场浸水试验过程中真实测定孔隙气压演化规律鲜有报道。因此,笔者开展黄土高原大厚度自重湿陷性黄土场地现场浸水试坑试验,在典型剖面不同深度布置湿度传感器和孔隙压力传感器,直接测定浸水过程中水分运移和孔隙气体压力,揭示水分运移和气压形成规律。研究结果表明,试坑浸水-停水过程中,呈现出水分入渗的感知-增湿-饱和-减湿-稳定的5阶段变化规律;打设注水孔,明显地改变了试坑中的水分扩散路径,以注水孔的径向渗流——古土壤富水向上迁移的扩散路径为主;首次实现了在大厚度湿陷性黄土大型试坑浸水过程中土体孔隙气压力的原位测定,呈现波动特征,提出了浸水过程中孔隙气压的形成模式。成果为非饱和黄土中水-气运移过程提供实测证据,为进一步精细化预测大厚度黄土的增湿湿陷过程奠定基础。In the Loess Plateau of the Yellow River Basin,loess disasters are frequent,and the key geologic gene is that the loess is extremely sensitivity to water.Among them,the scientific evaluation of wetting-induced collapse deformation of loess site is one of the themes. The wetting-induced collapse deformation of loess site gradually changes from "maximum potential" to "possible potential", and there is an urgent need to find out the multi-field coupling process of water infiltration, gas migration, and wetting-induced collapse deformation in loess during the on-site pit immersion test. At present, there are few reports about the measured pore gas pressure and its evolution law during the on-site pit immersion test. Accordingly, the site immersion test in loess plateau site on large thickness of self-weighted wetted loess were carried out. Moisture sensors and pore pressure sensors were arranged at different depths of typical profiles, to directly measure the water transport and pore gas pressure during the water immersion process, and thus then reveal the water transport and gas pressure formation laws. The results show that the 5-stage change rule of perception of water infiltration - wetting - saturation -drying - stabilization during the on-site pit immersion after stoping. The installation of water injection holes has obviously changed the water diffusion paths in the pit, and the radial seepage from the injection holes and the enrichment of water near paleosoil stratigraphy, whereby resulting in a predominantly upward migration of water. Having realized for the first time, the in-situ measurement of pore gas pressure of the soil during soaking in a large test pit on large thickness of the collapsed loess site. It showed fluctuating changes, and the formation mode of the pore gas pressure during soaking was proposed. The results provided experimental evidence of the coupled water-gas transport in unsaturated loess, and lay the foundation for further refinement of the prediction of the wetting-induced collpase of

关 键 词：黄土灾害 大厚度自重湿陷性黄土 浸水试验 水分入渗 孔隙气压 

分 类 号：P642.23[天文地球—工程地质学]