基于数值模拟的自锚试桩Q-s曲线转换

Q-s curve conversion of self-anchored test pile based on numerical simulation

为解决自锚试桩荷载-位移(Q-s)曲线向传统试桩Q-s曲线转换的问题,首先采用数值模拟对比分析顶拔桩、桩端无土顶压桩、传统试桩和自锚试桩这4种不同模拟桩的Q-s曲线,基于荷载相等原则,引入位移转换系数,建立了自锚试桩Q-s曲线向传统试桩Q-s曲线转换公式;然后通过转换公式对Q-s曲线及试验Q-s曲线进行了转换。结果表明:在粉土中,将模拟的自锚试桩上、下段桩Q-s曲线转换为模拟的传统试桩的Q-s曲线,得到的极限承载力为2840N,与传统试桩相比相差仅为1.4%,得出的Q-s转换曲线与传统试桩的Q-s曲线高度吻合;试验得出的自锚试桩Q-s转换曲线与试验传统试桩相比,极限承载力的误差为1.4%,沉降量误差为17.6%;数值模拟与试验得出的两种转换曲线相比,两者得出的极限承载力相同,软件模拟的自锚试桩总沉降量比试验得出的略小一些,相差仅为7.2%。该Q-s曲线转换公式可以为自锚试桩向传统静载荷试桩Q-s曲线转换提供可行的方法。

In order to solve the problem of conversion from load displacement(Q-s)curve of selfanchored test piles to Q-s curve of traditional test piles,the Q-s curves of four kinds of simulated piles,namely,tensile pile,top-pressed pile(without soil under the pile),traditional test pile and self-anchored test pile,were compared and studied by numerical tests.Based on the principle of load equality and displacement conversion coefficient,the conversion formula of Q-s curve from the self-anchored test pile to the traditional test pile was established.Then,the Q-s curve and Q-s test curve were converted by the conversion formula.The results showed that the ultimate bearing capacity was 2840Nwhen the Q-s curve of the upper and lower sections of the simulated self-anchored test pile was converted into the Q-s curve of the simulated traditional test pile in the silt,and the difference was only 1.4%compared with the traditional test pile.The obtained Q-s conversion curve was highly consistent with the Q-s curve of the traditional test pile.Compared with the traditional test pile,the ultimate bearing capacity and settlement error of the Q-s conversion curve of the self-anchored test pile obtained from the test were 1.4%and 17.6%respectively.Compared with the two conversion curves obtained from numerical simulation and the test,the ultimate bearing capacity obtained from both was the same.The total settlement of the selfanchored test pile simulated by the software was slightly smaller than that obtained from the test,and the difference was only 7.2%.The Q-s curve conversion formula can provide a feasible method for the conversion from the self-anchored pile to the traditional static load test pile.