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通过不固结不排水三轴压缩试验研究纤维长度(3~18 mm)、纤维掺量(0.1%~0.3%)和围压(30~300 k Pa)对聚丙烯纤维三维加筋风沙土强度特性的影响。试验结果表明:在试验方案内,纤维长度、纤维掺量和围压的提高均能有效地增强纤维加筋风沙土的破坏强度和残余强度。随着纤维长度和掺量的增加,纤维加筋风沙土黏聚力提升显著,而内摩擦角提升微小。纤维长度的增加可使纤维加筋风沙土应变软化型过渡为应变硬化型,破坏韧性提高微小。随着纤维掺量的增加,3 mm纤维加筋风沙土始终保持为应变软化型,破坏韧性没有提升;9和18 mm纤维加筋风沙土均由应变软化型过渡为应变硬化型,破坏韧性明显提升。随着围压的增加,纤维加筋风沙土破坏韧性和应变硬化程度得以提高。破坏强度与围压关系以临界围压为转折点呈双线性。临界围压前,加筋作用主要体现为内摩擦角的提升;临界围压后,加筋作用主要体现在黏聚力的增强。
The effects of fiber length (3 ~ 18 mm), fiber content (0.1% ~ 0.3%) and confining pressure (30 ~ 300 kPa) on strength of 3D reinforced aeolian sandy soil Effect of characteristics. The experimental results show that the increase of fiber length, fiber content and confining pressure can effectively enhance the failure strength and residual strength of fiber reinforced aeolian sandy soil. With the increase of fiber length and content, the cohesion of fiber reinforced aeolian sandy soil increased significantly, while the internal friction angle increased slightly. The increase of fiber length can make the fiber-reinforced aeolian sandy soil strain-softening transition to strain-hardening type, and the damage toughness increase slightly. With the increase of the fiber content, the 3 mm fiber reinforced aeolian sandy soil remained the strain softening type and the failure toughness did not increase. The 9 and 18 mm fiber reinforced aeolian sandy soil both changed from strain softening to strain hardening, and the fracture toughness was obvious Enhance. With the increase of confining pressure, the failure toughness and degree of strain hardening of fiber reinforced aeolian sand can be improved. The relation between failure strength and confining pressure is bilinear with the critical confining pressure as the turning point. Before the critical confining pressure, the reinforcing effect is mainly reflected by the increase of the internal friction angle. After the critical confining pressure, the reinforcing effect is mainly reflected in the enhancement of cohesion.