聚氨酯型固化剂加固砂性土抗压试验及破坏模式

针对砂性土结构松散的问题,采用聚氨酯型固化剂对其进行改良,对不同固化剂含量及养护时间的改良砂性土进行了无侧限抗压试验,并对其加固程度及破坏模式进行分析。结果表明:聚氨酯型固化剂改良的砂性土无侧限抗压强度得到一定程度的提高;当养护时间一定时,改良砂性土的抗压强度和残余强度随着固化剂含量增加而增加,峰值应变反而减小;当固化剂含量一定时,改良砂性土的抗压强度。残余强度及峰值应变均随着养护时间增加而增加;抗压强度、残余强度及峰值强度在含量为30%,养护时间为48 h时,基本达到最佳加固效果;在无侧限压缩破坏后,养护初期的破坏形态为“X”形、“Y”形剪切带破坏,在养护中期为“花瓣状”破坏,养护后期为锥形缝合线状破坏。

Unconfined Compression Test and Failure Mode of Sandy Soil Stabilized by Polyurethane Soil Stabilizer

The sandy soil is unconsolidated. The characteristics of strength and failure pattern of the sandy soil reinforced by polyurethane soil stabilizer were analyzed according to the unconfined compression test. The results show that the unconfined compressive strength of reinforced sandy soil increases with the increase of polyurethane contents, while the peak strains decrease; at the same curing time, the compressive strength, residual strength of reinforced sandy soil increase with the increase of polyurethane content, while the peak strain decreases; at the same polyurethane content, the compressive strength, residual strength and peak strain of reinforced sandy soil increase with the increase of curing time; the effects of compressive strength, residual strength and peak strength are best with the polyurethane content of 30% and at the curing time of 48 h; for the unconfined compression test, the failure modes of samples are X-shape or Y-shape shear bands after the curing time of 6 h, petal-shape after the curing time of 12-48 h, and zigzag-shape after the curing time of 72 h.