矩形顶管近距离下穿给水管线变形控制技术

Deformation Control Technology of Rectangular Pipe Jacking Through Water Supply Pipeline at Close Distance

城市地下通道建设中采用顶管施工时,近距离下穿对沉降敏感的浅埋管线这一工况越发普遍。由于绝大部分管线关系到当地水电气安全供应,直接影响城市居民正常生活,因此,施工中对其变形控制提出更高要求。以上海地铁18号线下盐路地铁站出入口矩形顶管近距离下穿给水管线施工项目为依托,通过数值计算与现场实测数据对比,分析了矩形顶管顶进施工过程中对附近地面和管线的扰动特性。采用不同的地层损失量和土仓压力进行数值分析,提出变形控制技术参数,并得到相关研究结论:顶管施工土仓压力控制在0.08~0.12MPa可有效控制地表沉降,纵向监控范围宜为工作面前方20m、工作面后方15m,横向监控范围宜为管线左、右20m,地层损失是引起地表和管线沉降的最重要因素。

In construction of urban underground passages by pipe jacking,it is more and more common to pass through the shallow buried pipeline which is sensitive to settlement at close range.Since most pipelines are related to water and electricity supply,they directly affect the normal life of the urban residents.Therefore,higher deformation control requirements are put forward during construction.Based on the rectangular pipe jacking short distance passing through water pipeline underneath the passage of Xiayan Road subway station of Shanghai Subway Line 18,this paper analyzes the disturbance characteristics of rectangular pipe jacking construction to nearby ground and pipelines by numerical simulation,and compares with the field measured data.Taking different soil loss and support pressure for numerical analysis,this paper draws technical parameters of deformation control and relevant conclusions:The support pressure in pipe jacking construction should be controlled between 0.08MPa and 0.12MPa to effectively control surface settlement;The longitudinal monitoring range should be 20m in front of the working face and 15m behind the working face;The transverse monitoring range should be about 20m around the pipeline.The most important factor of ground surface and line settlement is soil loss.