输水盾构隧洞管片环缝抗剪机制试验研究——以三门核电站取排水隧洞为例

Shear Mechanism of Circumferential Joint of Water Conveyance Shield Tunnel Segment: a Case Study on Intake and Drainage Tunnels of Sanmen Nuclear Power Plant

为研究三门核电站2期输水盾构隧洞管片环缝的力学性能,开展环缝径向抗剪试验和切向抗剪试验。对于径向抗剪试验,设置理想拼装和凹凸榫搭接2种工况,并测试每种工况下不同环间残余荷载时环缝的抗剪性能;对于切向抗剪试验,仅对理想拼装工况开展试验。试验结果表明:1)当拼装理想时,环缝首先由静摩擦力单独承担剪切力,再由摩擦力和凹凸榫共同承担剪切力;而当拼装导致凹凸榫搭接时,环缝直接由摩擦力和凹凸榫共同承担剪切力。2)环缝切向抗剪分为摩擦力单独作用、摩擦力与螺栓共同作用及摩擦力、螺栓与凹凸榫混凝土三者共同作用3个阶段。3)在环缝错动之前,环缝径向剪切刚度为4.67×10^(8)~1.42×10^(9) N/m,切向剪切刚度可取为4.23×10^(8)~8.43×10^(8) N/m。4)纵向力越大,剪切刚度越大。

The present study aims to investigate the mechanical properties of the circumferential joint of water conveyance shield tunnel at the Sanmen nuclear power plant(phase Ⅱ). For this, radial and tangential shear tests are conducted. In order to examine the shear properties of circumferential joints under various residual loads, the radial shear test is conducted under the ideal assembling condition and the concave and convex tenon connection condition. In comparison, the tangential shear test is conducted only under the ideal assembling condition. The results of the research reveal the following:(1) Under ideal assembling condition, the shear force is first borne by static friction and then by friction and tenon. Under the concave and convex tenon connection condition, the shear force is borne by friction and tenon.(2) The static friction, bolt, and tenon concrete act in succession in the tangential shear test.(3) The radial shear stiffness ranges from 4.67×10^(8) to 1.42×10^(9) N/m, and the tangential shear stiffness ranges from 4.23×10^(8) to 8.43×10^(8) N/m before dislocation of circumferential joints.(4) The larger is the longitudinal force, the higher is shear stiffness.