现场试坑浸水试验在湿陷性黄土地区地铁工程中的应用
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摘要
大厚度湿陷性黄土地基处理是黄土地区地铁建设中所面临的主要技术难题,采用传统的室内试验评价湿陷性的方法具有一定的局限性。本文采用数值模拟方法分析了地铁工程基底湿陷性黄土应力特征,在此基础上,通过现场试坑浸水试验,准确判定了黄土场地湿陷类型及自重湿陷下限深度,研究了大厚度湿陷性黄土场地浸水过程中的自重湿陷变形特征、水分场的时空运移、土压力(竖向及侧向)、侧向位移的变化规律,查明了浸水影响范围及地面裂缝影响范围,确定了自重湿陷的地区土质修正系数β0,为湿陷性黄土地区地铁工程的地基处理提供依据。
Foundation treatment method of collapse loess with large thickness is the main technical problem in the subway construction in loess areas. It is limited to use the traditional laboratory test to evaluate the collapsibility. The stress characteristics of collapsible loess in the subway engineering basement are analyzed by numerical simulation method. On this basis,the wet subsidence type of the loess site and self-weight collapse depth are accurately determined through the site pit soaking test. Also,self-weighted collapsed deformation characteristics,temporal and spatial migration of water separation field,soil pressure(vertical and lateral) and lateral displacement changing law during the immersion process of the large thickness collapsible loess site are studied. The influence range of water immersion and ground cracks are investigated,and the soil quality correction factor β0 is determine. Which provide the basis for ground treatment of subway engineering in collapsible loess Regions.
Foundation treatment method of collapse loess with large thickness is the main technical problem in the subway construction in loess areas. It is limited to use the traditional laboratory test to evaluate the collapsibility. The stress characteristics of collapsible loess in the subway engineering basement are analyzed by numerical simulation method. On this basis,the wet subsidence type of the loess site and self-weight collapse depth are accurately determined through the site pit soaking test. Also,self-weighted collapsed deformation characteristics,temporal and spatial migration of water separation field,soil pressure(vertical and lateral) and lateral displacement changing law during the immersion process of the large thickness collapsible loess site are studied. The influence range of water immersion and ground cracks are investigated,and the soil quality correction factor β0 is determine. Which provide the basis for ground treatment of subway engineering in collapsible loess Regions.
引文
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[7]马闫,王家鼎,彭淑君,等.大厚度黄土自重湿陷性场地浸水湿陷变形特征研究[J].岩土工程学报. 2014. 36(03):537-546.
[8]李开超,高虎艳,郑建国,等.西安地铁四号线南段大厚度湿陷性黄土浸水试验研究[J].地下水. 2017.(02):133-137.
[2]李大展,何颐华,隋国秀. Q2黄土大面积浸水试验研究[J].岩土工程学报. 1993. 15(2):1-11.
[3]王小军,米维军,熊治文,等.郑西客运专线黄土地基湿陷性现场浸水试验研究.铁道学报[J]. 2012. 34(1):83-90.
[4]黄雪峰,陈正汉,哈双,等.大厚度自重湿陷性黄土场地湿陷变形特征的大型现场浸水试验研究[J].岩土工程学报. 2006. 28(3):382-389.
[5]张炜,张苏民,郑建国.我国湿陷性黄土工程评价中若干问题的探讨[R].青岛:中国地质学会工程地质专业委员会(第九届全国工程地质大会). 2012.
[6]姚志华,黄雪峰,陈正汉,等.兰州地区大厚度自垂湿陷性黄土场地浸水试验综合观测研究[J].岩土工程学报. 2012.(01):65-74.
[7]马闫,王家鼎,彭淑君,等.大厚度黄土自重湿陷性场地浸水湿陷变形特征研究[J].岩土工程学报. 2014. 36(03):537-546.
[8]李开超,高虎艳,郑建国,等.西安地铁四号线南段大厚度湿陷性黄土浸水试验研究[J].地下水. 2017.(02):133-137.