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对掺砂改良后的膨胀土进行了干湿循环作用下的无荷膨胀率试验,研究了试样的无荷膨胀率(绝对膨胀率)、相对膨胀率以及终止吸水量随干湿循环次数的变化规律,深入分析了不同干湿循环次数后,改良膨胀土的膨胀量随浸水时间的增长特征.试验表明:1)无荷膨胀率以及终止吸水量随干湿次数的增长变化规律基本一致,在相同的风化砂掺量下,无荷膨胀率呈3次函数形式降低,且无荷膨胀率在第2~3次干湿循环后,降低幅度较大,之后降低幅度逐渐减小,最后基本趋于稳定;2)掺风化砂对抑制无荷膨胀的发生效果不大,当风化砂由0增至50%时,无荷膨胀率降低幅度较小,且这一降低幅度随着干湿循环次数的增大为逐渐减小;3)无荷膨胀量在浸水1h内的增长速度较快,之后逐渐变缓,在相同的风化砂掺量下,无荷膨胀量达到稳定时的时间随着干湿循环次数的增加而逐渐缩短.
The tests of no-load expansion rate under dry-wet cycles were carried out on the expansive soils modified with sand. The unloaded expansion rate (absolute expansion rate), relative expansion rate The results show that: 1) The law of non-load expansion and the change of water absorption capacity with the increase of wet-dry times are basically the same, Under the same amount of weathered sand, the unloaded expansion rate decreased in the form of cubic function, and the unloaded expansion rate decreased greatly after the 2nd to 3rd wet-dry cycles, then decreased gradually, and finally the basic Tends to be stable. 2) The effect of aerated sand on the suppression of unloaded expansion is not obvious. When the aerated sand increases from 0 to 50%, the decrease of unloaded expansion is smaller, The increase of the number decreases gradually; 3) The rate of no-load expansion increases rapidly within 1h of soaking and then gradually becomes slower. With the same amount of weathered sand, the time of no-load expansion stabilizes with The number of wet and dry cycles increased and gradually shortened.