人工冻融海相黏土微观孔隙特征试验研究

Experimental Study on Micro-pore Characteristics of Marine Clay due to Artificial Freeze-thaw

针对海相黏土的强结构性,结合微观孔隙特点,定量分析了压汞试验海相黏土冻融及压缩前后进汞压力与进汞增量的变化关系,获得了4种工况下的土体孔径、孔表面积的定量变化规律。结果表明,原状软黏土经冻融、压缩作用后孔隙分布发生改变,各类孔隙在数量分布上也发生改变,部分较大的孔隙破裂分解成中小孔隙,或部分小孔隙连通成狭长的中大孔隙,孔隙变化情况复杂;同冷端温度条件下冻融及压缩后,孔径-对数进汞增量曲线对应峰值处,最大进汞增量及对应孔径差异较大;对于冻融后的压缩土,在外荷载作用下,峰值处对应的最大进汞增量均降低约50%,孔径与进汞压力为负对应关系。

According to the strong structure of marine clay and the characteristics of micro pores,the relationship between mercury intake pressure and mercury intake increment before and after freeze-thaw and compression of marine clay is quantitatively analyzed,and the quantitative change rules of soil pore size and pore surface area are obtained under four working conditions.The results show that the pore distribution of undisturbed soft clay is changed after freeze-thaw and compression,and the quantity distribution of all kinds of pores is also changed.Some larger pores are broken down into small and medium pores,or some small pores are connected with narrow and large pores,and the pore changes are complicated.After freeze-thaw and compression at the same cold end temperature,the maximum increment of mercury intake and the corresponding pore diameter are significantly different at the corresponding peak of the pore-logarithmic mercury intake curve.For the compressed soil after freeze-thaw,under the action of external load,the maximum increment of mercury intake at the peak decreases by about 50%,and there is a negative correlation between the pore diameter and the mercury intake pressure.