多因素影响下砒砂岩的融沉特性试验研究

目的]探究融沉作用对砒砂岩结构改变,揭示砒砂岩冻融侵蚀机理。方法]使用高低温交变湿热试验箱H/GDWJS-100L对砒砂岩进行不同含水率、不同冻结温度、不同干密度下的冻融试验。结果]含水率低于11%的砒砂岩,冻胀量随着含水率的变化较小,含水率大于11%后冻胀量随着含水率的增加变化显著;在融化的过程中,砒砂岩存在起始融沉含水率在13%附近,当含水率大于起始融沉含水率发生融沉,否则发生融胀;砒砂岩融化时最大位移变化量与干密度有关,干密度1.80g/cm3对应试件的最大位移变化量最小;相同含水率、干密度条件下的砒砂岩融化时的最大位移变化量,随着冻结温度的降低而增大。结论]冻融过程中砒砂岩的位移变化引起颗粒间的重新排列,使其孔隙特征发生变化,从而导致砒砂岩结构的改变。

Experimental Study on Thawing Settlement Performance of Feldspathic Standstone Subjected to Various Factors

Objective] In order to reveal the structural change of feldspathic sandstone caused by thaw collapse, the mechanism of the freezing and thawing erosion of feldspathic sandstone was discussed. Methods] Freezing-thawing tests were conducted using high-low temperature heat chamber H/GDWJS-100L with different moisture content, different freezing temperature and different dry densities. Results] The amount of frost heave changed slightly when the moisture content of feldspathic sandstone was below 11%, while it increased significantly when the moisture content was over 11%. In the process of thawing, the initial thawing settlement moisture content was about 13%. When the moisture content was higher than 13%, thaw settlement occurred, otherwise, frost heave occurred. The maximum displacement of the feldspathic sandstone was closely related to dry density, the variation of maximal displacement was the least when dry density was 1.80 g/cm³. With the same moisture content and dry density, the maximum displacement of the feldspathic sandstone during melting increased with the decrease of temperature. Conclusion] In the process of freezing-thawing, the displacement of feldspathic sandstone can cause the rearrangement of particles and the change of the pore characteristic, resulting in the structure change of feldspathic sandstone.