泥水平衡盾构渣浆处理及循环利用技术发展现状

目前,泥水平衡盾构主要应用于过江隧道及城市富水隧道施工,但是其施工程中产生了大量废弃泥浆,大部分企业采用外运方式,造成了土地资源的浪费和生态环境的污染.如何以更为高效、环保、低能耗的方式处理这些废弃物,一直是关注的焦点.首先介绍了泥水平衡盾构渣浆处理系统,然后总结了目前渣浆处理的3种主要方式:①利用盾构渣浆作为壁后注浆...     

Upper bound solution for supporting pressure acting on shallow tunnel based on modified tangential technique

Based on the nonlinear failure criterion and the upper bound theorem, the modified tangential technique method was proposed to derive the expression of supporting pressure acting on shallow tunnel. Instead of the same stress state, different normal stresses on element boundaries were used. In order to investigate the influence of different factors on supporting pressures, the failure mechanism was established. The solution of supporting pressure, with different parameters, was obtained by optimization theory. The corresponding failure mechanism and numerical results were presented. In comparison with the results using the single tangential technique method, it is found that the proposed method is effective, and the good agreement shows that the present solution of supporting pressure is reliable.     

Kinematical analysis of highway tunnel collapse using nonlinear failure criterion简

For different kinds of rocks, the collapse range of tunnel was studied in the previously published literature. However, some tunnels were buried in soils, and test data showed that the strength envelopes of the soils followed power-law failure criterion. In this work, deep buried highway tunnel with large section was taken as objective, and the basic expressions of collapse shape and region were deduced for the highway tunnels in soils, based on kinematical approach and power-law failure criterion. In order to see the effectiveness of the proposed expressions, the solutions presented in this work agree well with previous results if the nonlinear failure criterion is reduced to a linear Mohr-Coulomb failure criterion. The present results are compared with practical projects and tunnel design code. The numerical results show that the height and width of tunnel collapse are greatly affected by the nonlinear criterion for the tunnel in soil.