兰州地区大厚度自重湿陷性黄土场地浸水试验综合观测研究  

Comprehensive soaking tests on self-weight collapse loess with heavy section in Lanzhou region

作　　者：姚志华[1] 黄雪峰[1,2] 陈正汉[1] 张建华[3] 

机构地区：[1]解放军后勤工程学院建筑工程系,重庆401331 [2]兰州理工大学土木工程学院,甘肃兰州730050 [3]中煤邯郸设计工程有限责任公司,河北邯郸056031

出　　处：《岩土工程学报》2012年第1期65-74,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(11072265);国家电网公司科学技术项目(SGKJJSKF[2008]656);重庆市科委自然科学基金项目(2009BB6174)

摘　　要：对兰州地区Q3大厚度自重湿陷性黄土场地进行了不设注水孔,埋设水分计和热传导吸力探头的浸水试验。研究结果表明:大厚度黄土场地的不同深度土层均会出现多次湿陷,湿陷次数随着土层深度的增加将减少;体积含水率在不同深度土层中呈现不同的变化规律,10 m以上基本由6段组成,10～22.5 m由5段组成,而22.5 m以下则由3段组成;25 m以上范围内水分入渗较为容易,该深度以下土层,由于上部土体发生湿陷压密以及空隙中的气体压力增大导致了水分入渗缓慢;离试坑周边较远的裂缝的产生由于试坑较近裂缝剧烈活动引起;水分运移基本呈现椭圆状形态入渗(长轴位于水平向),后期整个椭圆状湿润区的离心率越来越小,椭圆更扁;浸润角随着外部水源不断供给逐渐扩大,本次试验其变化范围在0°～55°;场地中水分入渗率基本呈现出幂函数减趋势。Soaking tests on self-weight collapse Q3 loess with heavy section located in Lanzhou region are conducted without water injection hole and with moisture meter and heat conduction suction probe embedded. The test results indicate that multiple collapses appear in different soil layers at different depths, and the times of the collapses decrease with the increase of loess depth. The volumetric water content at different depths has different rules： the curve above 10 m in depth is made up of 6 stages, that between 10 m and 22.5 m in depth has 5 stages, and that beneath 22.5 m in depth has 3 stages. The water above 25 m in depth infiltrates easily, and the water beneath 25 m in depth infiltrates slowly because the upper loess has collapsibility inducing the compaction and air pressure among soil pores increases gradually. The cracks far from the test pit are generated by the violent motion of the cracks near the test pit. The wetting front of the self-weight collapse loess with heavy section takes the shape of an ellipse （the major axis is horizontal）, and finally the eccentricity of elliptical humidification area becomes less. The soggy angle increases with the increasing supply of water source, and its variation range is 0° -55 ° . The vertical infiltration velocity presents the reduction tendency of power function.

关 键 词：大厚度自重湿陷性黄土 浸水试验 体积含水率 吸力 渗透 浸润角 

分 类 号：TU444[建筑科学—岩土工程]