考虑毛细水负压力引起坑外场地沉降量计算方法和潜在威胁性研究

为得出毛细水负压力对坑外场地土体沉降影响,从而更准确计算出因坑内水位降深引起的坑外土体沉降量。借用海森(Hazen A)经验公式进行估算水位下降后毛细水上升高度,进一步得出毛细作用产生的负压力。在规范给出的分层总和法计算土体沉降基础上,给出考虑毛细水负压力计算土体沉降方法,为计算坑内降水造成周边土体沉降提供参考。通过该计算方法分别分析在不同孔隙比、有效粒径条件下,毛细水负压力对土体沉降的影响性。结果表明毛细水上升高度随着土体粒径及孔隙比的减小而增大,尤其当土体有效粒径小于0.075 mm时,应着重考虑考虑毛细水负压对土体沉降影响。

Study on calculation method and potential threat of settlement outside foundation pit considering negative pressure of capillary water

This paper uses the empirical formula of A. Hazen to estimate the rising height of capillary water after the water drawdowns, and then gets the negative pressure produced by capillary water. Based on the layered summation method given in the code, a method for calculating the settlement of soil considering negative capillary water pressure is presented, which can provide a reference for calculating the settlement of surrounding soil caused by precipitation in foundation pit. The calculation method is used to analyze the different pore ratio and effective diameter, the influence of negative pressure of capillary water on soil settlement. The results show that the elevation of capillary water increases with the decrease of soil effective diameter and void ratio, especially when the effective diameter of soil is less than 0.075 mm, the influence of capillary water negative pressure on soil settlement should be considered.