深埋大断面钢结构顶管接触压力及受力特性现场试验研究

Field Test Research on the Contact Pressure and Stress Characteristics of Jacked Steel Pipes with Deep-buried Depth and Large-section

为研究深埋超大断面钢结构顶管外荷载的空间分布与变化规律、注浆荷载的影响以及结构受力特性等,文章以上海轨道交通14号线静安寺站顶管隧道为工程背景,采用水土压力计和应变计对其进行现场监测试验,并对外荷载和结构应变进行数据采集和整理分析。研究结果表明:稳定荷载工况下,管节外荷载沿环向分布整体呈梨形,其中,管节顶部水土总压力实测值与理论值基本一致;施工过程中的注浆荷载可算作1倍顶部总压力稳定值;格构钢管节仍符合平截面假定;管节间的内力传递对环向应力应变有较大影响,顶管环缝纵向力会影响环缝刚度,进而影响内力传递系数;地面偶然荷载使得结构外荷载产生极大增量但结构应变增量较小。

In order to study the spatial distribution and variation pattern of the external load of deep-buried oversized-section steel pipes in pipe jacking construction,the effect of grouting load and the structural stress characteristics,etc.,taking the tunnel project of Jing'an Temple Station of Shanghai Rail Line 14,which is constructed by pipe jacking method,as the research context,this paper carries out field monitoring and tests by using water and soil pressure gauges and strain gauges,and followed by collection,processing and analysis of the external load and structural strain data.The research results show that under the steady load condition,the circumferential distribution of the external load of the pipe segment is generally in pear-shape,while the measured values of the total soil and water pressure at the top of the pipe segment is basically consistent with the theoretical values;grouting loads during construction can be counted as 1 time the total stable pressure at the top;the latticed steel pipe segment still conform to the plane section assumption;the internal force transfer between the pipe segments has a large impact on the circumferential stress and strain,and the longitudinal force at the pipe segment ring joint affects the stiffness of the ring joint,which in turn affects the internal force transfer coefficient;the incidental ground load causes a great increment in the external load of the structure but a small increment in the strain of the structure.