Analytical Solution of Excess Pore Water Pressure Caused by Shield Tunneling

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.

Key words:shield tunneling; MohrCoulomb yield criterion; friction angle; excess pore water pressure; analytical solutions; earth pressure of soil cabin