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毛细现象使得潮湿粉细砂土间的接触压力增加,如何计算砂土在这种情况下的强度,这是一个难题。从毛细水提供附加小主应力的角度出发,推导出了潮湿砂土在极限状态下的强度表达式,并用该式计算了在不同含水量下潮湿粉细砂土破坏时的大主应力。研究结果表明:当砂土中的毛细水量增加时,计算的大主应力是先增大后减小,当含水量大于10%时,潮湿砂的大主应力小于干砂的大主应力值,当达到饱和状态时,湿砂的大主应力达到最小值;将大主应力计算值与试验数据的反算值进行比较,发现两者比较接近;强度表达式中F1、F2随含水量的变化情况表明,F1、F2皆随含水量成二次函数变化;小主应力增量随含水量的变化情况,当含水量在0~11%的范围变化时,小主应力增量为正值,且存在一个最大值,则总的小主应力是增加的,潮湿粉细砂的强度是增大的;当含水量的变化范围为11%~31%时,小主应力增量为负值,则总的小主应力是减小的,潮湿粉细砂的强度也是减小的,以上计算结果同大主应力增量是相对应的。
The capillary phenomenon makes contact pressure between wet fine sand increased, how to calculate the strength of sand in this case, which is a problem. From the perspective of capillary water to provide additional small principal stress, the intensity expression of wet sand in the limit state is deduced, and the principal principal stress of the wet sand at different water content is calculated. The results show that when the capillary water in sand increases, the calculated principal principal stress firstly increases and then decreases. When the water content is more than 10%, the principal principal stress of wet sand is smaller than that of dry sand, When the saturated state is reached, the main stress of the wet sand reaches the minimum value. Comparing the calculated value of the principal stress with the calculated value of the experimental data, it is found that the two are close. The change of F1 and F2 with the water content in the intensity expression The results show that F1 and F2 all change quadratically with water content. The increment of small principal stress varies with the change of water content. When the water content varies from 0% to 11%, the increase of small principal stress is positive, And there is a maximum value, the total principal stress is increased, and the strength of wet sand is increased. When the water content changes from 11% to 31%, the increment of small principal stress is negative, The total principal stress is reduced, the strength of wet sand is also reduced, the above calculation results correspond to the principal stress increment.