盾构施工引起的超孔隙水压力解析解

Analytical Solution of Excess Pore Water Pressure Caused by Shield Tunneling

摘要:

基于MohrCoulomb屈服准则,在考虑土体的内摩擦角φ的情况下,推导了盾构通过时引起的超孔隙水压力的公式并与φ=0的情况作了比较,表明φ值使得塑性区范围和超孔隙水压力值变大.塑性区的范围和塑性区内超孔隙水压力的主要影响因素是盾构土舱压力,但弹塑性区交界处的超孔隙水压力值为a6ccosφ(a为Henkel系数,c为土的粘聚力),与土舱压力无关.以上海地铁10号线同济大学站—国权路站区间隧道为实例,对此进行现场监测,结果显示解析解与实测值吻合较好;提出开孔释放超孔隙水压力对策,经实践检验非常有效.

Abstract:

Based on MohrCoulomb yield criterion,an analytical solution of excess pore water pressure caused by shield tunneling is obtained by taking the friction angle into consideration.The formula is compared with that without considering friction angle.Results show that the yield range and excess pore water pressure will increase when friction angle being considered.The main factor of yield range and excess pore water pressure in the range is earth pressure of soil cabin.However,the maximum excess pore water pressure in elastic zone is a6ccosφ(a is Henkel coefficient,c is cohesion of soil),the value is unrelated to earth pressure of soil cabin mentioned above.A case study is made of the tunnel from Tongji Station to Guoquan Station of urban rail transit Line 10 of Shanghai,the analytical solution fits well with the monitoring results.The method of setting holes in the slab is proposed to reduce excess pore water pressure and good results are achieved.