开挖卸载负孔压的消散对围护结构的影响

Influence of Dissipation of Negative Pore Water Pressure on Retaining Structure during Excavation

分析并讨论了基坑开挖卸载情况下坑底和周围土体中超静孔压的消散规律,基于太沙基扩散方程,推导了由于开挖引起的超静孔压和有效应力的计算公式.通过算例分析研究了超静孔压消散对围护结构侧压力的影响,认为负的超静孔压的消散不利于基坑的稳定,快速施工可以充分利用开挖引起的负孔压.

The dissipation rule of excess pore water pressure induced by unloading in excavation is studied. Analytical formulas for calculating negative excess pore water pressure and effective stress are derived based on Terzaghi's diffusion equation. The influence of the dissipation of negative excess pore water pressure on lateral pressure acting on retaining structure is analyzed through a numerical example. The results indicate that the dissipation of negative excess pore water pressure is harmful to the stability of foundation pit and fast construction can make full use of the negative pore water pressure.