摘要
地裂缝是西安市最典型的地质灾害之一,地裂缝地段地铁隧道施工引起地层及地表沉降是较为突出的工程地质和岩土工程问题。文章以西安地铁六号线浅埋暗挖隧道穿过f8地裂缝为工程背景,基于有限元数值模拟,对地裂缝地段交叉中隔墙法(CRD工法)暗挖施工引起的地表沉降和隧道变形进行了分析。结果表明:暗挖施工引起的地表沉降随开挖进尺呈反S型曲线变化特征,地裂缝带上盘的开挖进尺影响范围大于下盘;隧道中心线地表沉降在地裂缝带出现错台且靠近上盘5 m处出现集中沉降区;地裂缝地段隧道暗挖施工对地表的影响区范围约为80 m即上盘约45 m、下盘约35 m,在此范围应考虑暗挖施工对附近地表建(构)筑物的影响;开挖过程中地裂缝带上盘沉降过程变长且大于下盘;地表横向变形曲线符合高斯分布,上盘沉降大于下盘,在上盘靠近地裂缝位置处地表沉降槽宽度、沉降量明显增大;距地裂缝带5 m处上盘拱顶出现最大沉降,其值为25 mm,而在地裂缝位置处拱底出现27 mm的隆起变形,拱顶和拱底变形在地裂缝带附近出现错台;地裂缝带隧道暗挖施工对拱顶、拱底影响区范围分别为50 m和55 m,靠近上盘地裂缝位置附近隧道暗挖施工衬砌应及时支护,防止土体塌落与隧道变形。研究结果可为西安地铁隧道穿越地裂缝带暗挖施工提供科学依据和技术指导。
Ground fissure is one of the most typical urban geo-hazards in Xi’an,and the stratum deformation and ground settlement caused by metro tunnel construction in the ground fissure section is a prominent engineering geological and geotechnical engineering problem. In this paper,the Xi ’an metro line 6 is taken as the engineering background,and the ground settlement and tunnel deformation induced by the excavation of CRD method in the ground fissure section is simulated with the finite element method. The results show that the ground surface settlement caused by excavation is characterized by an inverse s-shaped change and the excavation footage of the hanging wall have a greater influence range than that of the footwall in the ground fissure section. The ground surface settlement in the center line of the tunnel is staggered in the ground fracture zone and a concentrated settlement area appears at 5 m near the hanging wall of the ground fissure.The influence area of the shallow-buried excavation on the surface is about 80 m in ground fissure zone,whicht is about 45 m in the hanging wall and about 35 m in the footwall. In this range,the impact of the underground excavation on the nearby surface structures should be considered. In the process of excavation,the ground settlement process of the hanging wall is longer and larger than that of the footwall and the lateral deformation laws of the ground surface conforms to the Gaussian curve distribution. The settlement values of the hanging wall are larger than that of the footwall,and the width and settlement value of the tunnel groove increase at the position of the hanging wall near the ground fissure. The maximum settlement of the arch roof occurs at 5 m away from ground fissure,with a value of 25 mm,while the uplift deformation of 27 mm occurs on the arch bottom at the ground fissure zone. The deformation of the arch top and arch bottom is staggered near the ground fissure zone. The influence areas of the shallow-buried excavation of tunnel on the arch roof and bot
作者
徐明祥
黄强兵
王庆兵
李明锷
雷建
XU Mingxiang;HUANG Qiangbing;WANG Qingbing;LI Ming’e;LEI Jian(Department of Geological Engineering,Chang’an University,Xi’an,Shaanxi 710054,China;Institute of Geotechnical and Underground Engineering,Chang’an University,Xi’an,Shaanxi 710054,China;Beijing Municipal Road&Bridge Group Co,Ltd.,Beijing 100045,China)
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2020年第1期161-170,共10页
Hydrogeology & Engineering Geology
基金
国家自然科学基金面上项目(41372328
41772274)
关键词
地铁隧道
地裂缝
浅埋暗挖法
数值模拟
地表沉降
隧道变形
metro tunnel
ground fissure
shallow-buried excavation
numerical simulation
ground settlement
tunnel deformation
