西北和华北地区广泛分布的黄土受到季节性冻融循环的破坏,导致黄土构筑物强度逐渐降低,引发各种不良问题。采用新型高分子固化剂(SH)对黄土进行固化,开展室内冻融循环对固化黄土抗压、抗剪强度影响的试验研究。结果表明:加入固化剂SH可以显著提高黄土的抗压强度,SH掺量越高,黄土抗压强度提升越大,经冻融循环后强度损失率越小,质量损失率越低,试样完整性越好;固化黄土的抗剪强度随冻融循环次数增加而减少,冻融循环对黏聚力影响明显;固化黄土经历3~4次冻融循环后黏聚力与内摩擦角下降最大,5次后下降幅度减小并渐趋于稳定。试验结果为固化剂SH在黄土冻融区的推广及应用提供参考,并为黄土冻融区治理提供一些理论依据。
Abstract
Seasonal freeze-thaw cycles degrades the strength of loess structures in northwest and north China, giving rise to many problems. In this research, indoor freeze-thaw cycle test was carried out on loess solidified by the new polymer curing agent SH to examine the impact of freeze-thaw cycles on the compressive and shear strength of the solidified loess. Results unveiled that curing agent SH significantly improved the compressive strength of loess. The higher the SH content, the higher the strength of loess, the lower the loss rate after freeze-thaw cycle, the lower the mass loss rate, and the better integrity of solidified loess samples. The shear strength of solidified loess decreased with the increase of the number of freeze-thaw cycles. Freeze-thaw cycle also has an evident impact on cohesion. The cohesive force and internal friction angle of the solidified loess decreased the most after 3-4 freeze-thaw cycles; such decline attenuated and gradually stabilized after 5 times of freeze-thaw cycles. The research findings offer reference for the promotion and application of curing agent SH in the frozen-melt zone of loess, and provide some theoretical basis for the treatment of frozen-melt zone of loess.
关键词
黄土 /
冻融循环 /
SH固化剂:抗压强度 /
抗剪强度 /
黏聚力 /
内摩擦角
Key words
loess /
freeze-thaw cycle /
SH curing agent: compressive strength /
shear strength /
cohesion /
internal friction angle
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基金
山西省自然科学基金项目(201701D221224,201901D211020)
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