摘要
以某地铁车站局部双层暗挖段零距离垂直下穿既有市政隧道为工程背景,通过建立三维数值模型,模拟双层暗挖段施工过程,揭示既有市政隧道结构的沉降特性。市政隧道结构的模拟沉降曲线表明,两变形缝间的市政隧道结构呈现刚性整体沉降,变形缝两侧的市政隧道结构呈现出明显的差异沉降,验证了“先期形成两变形缝间市政隧道的竖向支撑体系”的施工歩序是合理的。通过分析不同施工阶段对市政隧道最终沉降占比的影响,发现导洞开挖阶段的影响最大(约占最终最大沉降值的80%)。依据研究成果,采用了有针对性的注浆加固、改进喷射混凝土工艺、千斤顶辅助支撑等措施,以抑制既有隧道结构的变形和差异沉降。
Based on the engineering background of a Double-deck Underground Excavation Section of Metro Station undercrossing existing municipal tunnel vertically with zero distance,a three-dimensional numerical model was established to simulate the construction process of double-layer underground excavation section,which reveals the settlement characteristics of the existing municipal tunnel structure.The simulated settlement curve of the municipal tunnel structure shows that the municipal tunnel structure between the two deformation joints presents rigid overall settlement,and the municipal tunnel structure on both sides of the deformation joints presents obvious differential settlement,which verifies that the construction sequence of“forming the vertical support system of the municipal tunnel between the two deformation joints in the first place”is reasonable.By analyzing the influence of different construction stages on the final settlement ratio of the municipal tunnel,it is found that the excavation stage has the greatest influence(accounting for about 80%of the final maximum settlement value).According to the research results,targeted measures such as grouting reinforcement,improved shotcrete technology and jack auxiliary support are adopted to restrain the deformation and differential settlement of the existing tunnel structure.
作者
房旭
Fang Xu(China Railway Engineering Design and Consulting Group Co.,Ltd.,Beijing 100055,China)
出处
《铁道勘察》
2019年第6期40-44,共5页
Railway Investigation and Surveying
关键词
地铁车站
双层暗挖
零距离下穿
市政隧道
风险分析
差异沉降
metro station
double-deck Underground Excavation
undercrossing with zero distance
municipal tunnel
risk analysis
differential settlement
