基坑支护桩非极限准主动土压力计算研究

目前基坑支护桩土压力计算多数是运用经典土压力理论或者规范经验法计算,而这些方法大多是基于极限平衡状态推导出来的,这与基坑工程非极限状态土体有明显差异。为此,在他人已有研究成果的基础上,运用水平层分析法并结合合理的假设,推导出介于初始状态与极限状态间的非极限状态的准主动土压力计算公式,从而改进了水平层分析法。经基坑工程实例分析表明,由此得出的准主动土压力与工程实测土压力基本相符,且较朗肯主动土压力法、水平分层分析法计算结果偏大,但小于静止土压力法的值,这符合非极限状态土压力规律;同时也说明本文假设的合理性及准主动土压力计算公式的正确性。

Calculation and Research on Non-Limit Quasi Active Earth Pressure of Pit Support Pile

At present the foundation pit supporting pile soil pressure calculation mostly applies the classical earth pressure theory or normative experience method, which deduced under the limit equilibrium state, and is significantly different from the foundation pit engineering under non-limit state of soil. Based on the previous research results, applies the method of level-layer analysis and combining with the reasonable assumption to deduce the calculation formula of quasi active earth pressure of non-limit state between initial state and limit state, and improves the method of level-layer analysis. Through the analysis of the foundation pit engineering examples, it shows that the obtained quasi active earth pressure value is basically consistent with the actual measured earth pressure, and the caculating result of the method of level-layer analysis relatively larger than the consequence of Rankine active earth pressure, but it is less than the static earth pressure value, which in line with the non-limit state law of earth pressure. It also illustrated reasonableness of the previous assumptions and correctness of quasi- active earth pressure formula.