强夯等效拟静力试验及拟静压力计算方法

Equivalent pseudo-static test and calculation method of pseudo static pressure of dynamic compaction

强夯处理后的地基承载力如何计算,目前没有设计依据。本文以某吹填土工程地基处理为背景,设计室内强夯等效拟静力试验,提出强夯等效静压力试验的试验条件,即夯锤大小形状相同条件下强夯的夯沉量与夯锤在静压力作用下的沉降相等。通过室内试验验证了强夯等效拟静力试验的可靠性。试验结果表明:强夯各击对应的拟静压力达到或超过地基的极限荷载,随着夯击次数的增加,拟静压力增加,夯锤下地基极限承载力亦增加;随着细粒含量的增加,拟静压力先增加后减少,当细粒含量为30%时,各击的拟静压力达到最大值。本文提出了强夯拟静力法计算方法,可以判断不同终夯标准情况下的地基承载力。拟静压力计算结果是实测结果的0.93~1.23倍,具有较高的精度。

There is no design basis to calculate the bearing capacity of the ground after dynamic compaction.Based on the ground treatment of a dredger fill project,the indoor dynamic compaction equivalent quasi-static test is designed,and the test conditions of dynamic compaction equivalent static method is put forward which is that under the condition of the same size and shape of the rammer,the tamping settlement of dynamic compaction equals to the rammer settlement under static pressure.The reliability of dynamic compaction equivalent quasi-static method test is verified by laboratory test.The test results show that the pseudo static pressure corresponding to each blow of dynamic compaction reaches or exceeds the ultimate load of ground;with the increase of tamping blows,pseudo static pressure increases,and the ground ultimate bearing capacity under rammer also increases;with the increase of fine particle content,the pseudo static pressure increases firstly and then decreases;when the fine particle content is 30%,the pseudo static pressure of each blow reaches the maximum.The calculation method of dynamic compaction quasi-static method presented in this paper could estimate the ground bearing capacity under different final compaction standards.The calculated result of pseudo static pressure is 0.93~1.23 times of the measured result,which is fairly accurate.