基于压汞试验的珠海软土微观孔隙特征分析

Analysis of microscopic pore characteristics of Zhuhai soft soil based on mercury intrusion method

软土的微观结构研究对工程建设具有重要意义。为探讨珠海软土的微观结构特征,通过压汞试验对珠海软土微观孔隙特征开展试验研究,结果表明:珠海软土孔隙直径分布在3 nm~338μm范围,总孔容位于0.2~0.3m L/g,平均孔径为50~85 nm;珠海软土孔隙特征曲线呈单峰分布,随着深度增加,土体孔隙体积逐渐减小,优势孔径逐渐减小,土体孔径更加集中;堆载预压对珠海软土处理效果显著,总孔容可降低15%,孔隙率可降低10%;根据累计进汞的百分比曲线明显存在2个转折点,珠海软土微观孔隙可分为微孔隙(<10 nm)、小孔隙(10~360 nm)及大孔隙(>360 nm),其中大孔隙约占4%,微孔隙约占5%。

It is of great significance to study the microstructure of soft soil for engineering construction.In order to investigate the microstructural characteristics of soft soil in Zhuhai,a series of mercury intrusion porosimetry(MIP)tests were conducted for soft soil samples.According to the test results,the pore diameter of soil is distributed in the range of 3 nm-338μm,the total pore volume is 0.2-0.3 mL/g,and the average pore diameter is 50-85 nm.The pore characteristics curves of soil samples show a single-peak distribution pattern.With the increase of depth,the pore volume of the soil gradually decreases,the dominant pore size gradually decreases,and the soil pore size is more concentrated.The effect of stack pre-pressure on soft soil is significant,the total pore volume can be reduced by 15%,and the porosity can be reduced by 10%.According to the cumulative mercury injection percentage curve,there are obviously two turning points,the microscopic pores of soft soil in Zhuhai can be divided into micro-pores(<10 nm),small pores(10-360 nm)and large pores(>360 nm),of which large pores account for about 4%and micro-pores account for about 5%.