摘要
水工隧洞衬砌外水压力折减系数的合理取值是结构设计中的难点。以引汉济渭引水隧洞工程穿越Q_(2)黄土地层为背景,开展了饱和Q_(2)黄土的物理力学特性试验,并基于FLAC3D有限差分法及流–固耦合分析原理,研究6种因素对外水压力折减系数的敏感程度和变化规律。结果表明,各因素对外水压力折减系数的影响程度从高到低依次为:壁后注浆厚度h>盾构掘进速度V>地层渗透系数k_(l)>开挖扰动范围w_(s)>壁后注浆水平N>地下水位高度H,壁后注浆厚度对外水压力折减系数影响最大,当盾构掘进速度V≤9 m/d、地层渗透系数k_(l)≤0.2 m/d时,外水压力折减系数受盾构掘进速度和地层的渗透系数影响较大,其余因素影响较小;考虑到地层条件及施工水平的差异性,饱和Q_(2)黄土中衬砌外水压力折减系数取值变化范围为0.35~0.75,平均可取0.53。
The reasonable value of the reduction coefficient of external water pressure(RCEWP)in hydraulic tunnel lining is a difficulty in structural design.Taking the hydraulic tunnel of the Hanjiang to Weihe River Valley Water Diversion Project crossing sat-urated Q_(2) loess stratum as an example,the physical and mechanical properties of Q_(2) loess were tested.Based on FLAC3D and coupled fluid-soild analysis method,the sensitivity degree and variation rule of six factors to the RCEWP were studied.The results show that:(1)The sensitivity degree of each factor on the RCEWP from high to low is as follows:The grouting thickness behind the lining(h)>speed of shield advancing(V)>permeability coefficient of loess stratum(k_(l))>disturbance zone due to excavation(w_(s))>grouting level(N)>groundwater table(H).The grouting thickness behind the lining has the greatest influence on the RCEWP.When the speed of shield advancing(V)≤9 m/d and the permeability coefficient of loess stratum k_(l)≤0.2 m/d,the RCEWP is greatly affected by them,while the other factors have little influence.(2)Considering the difference of stratum conditions and construction and management level,the RCEWP of lining in saturated Q_(2) loess ranges from 0.35 to 0.75,with an average value of 0.53.
作者
朱才辉
杨奇强
李玉波
宋晓峰
党辉
Zhu Caihui;Yang Qiqiang;Li Yubo;Song Xiaofeng;Dang Hui(Shaanxi Engineering Technology Research Center for Urban Geology and Underground Space,Xi’an 710068,Shaanxi,China;Shaanxi Hydrogeolog Engineering Geology and Environment Geology Survey Center,Xi’an 710068,Shaanxi,China;Institute of Geotechnical Engineering,Xi'an University of Technology,Xi'an 710048,Shaanxi,China;China Railway First Survey And Design Institute Group Co.,Ltd.,Xi'an 710043,Shaanxi,China;Hanjiang to Weihe River Valley Water Diversion Project Construction Co.,Ltd.,Shaanxi Province,Xi'an 710011,Shaanxi,China)
出处
《岩土工程技术》
2023年第6期656-663,共8页
Geotechnical Engineering Technique
基金
国家自然科学基金(52279110)
陕西省重点研发计划项目(2021SF2-02,2022SF-197)
陕西省自然科学基金资助项目(2019JLP-22)
陕西省城市地质与地下空间工程技术研究中心开放性课题(2022KT-01)。
关键词
Q_(2)黄土
外水压力折减系数
水工隧洞
流–固耦合分析
Q_(2) loess
reduction coefficient of external water pressure(RCEWP)
hydraulic tunnel
coupled fluid-solid analysis
