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对土工格栅加筋黏性土进行不固结不排水的动态三轴振动试验。试验结果表明,在黏性土中布置格栅筋材,在一定程度上能提高加筋土体的动抗剪强度;加筋层数越多,加筋土动强度越大;土工格栅加筋黏性土的加筋效果在高围压下能够更好地发挥。加筋土动强度指标提高体现在动黏聚力的增大上,而对动摩擦角几乎没有影响,循环荷载振动次数对动强度指标影响很小;动应力幅值对于周期荷载下加筋土的变形影响很大,在动应力幅值大的周期荷载作用下变形增加很快,在较小的振动周次作用下就可使试样破坏,相反,动应力幅值低的试样,则需要大的振动周次才能达到破坏应变;加筋土体存在一临界破坏动应力,当设置的动应力振幅小于临界值时,无论振动多少次,试样都达不到破坏应变;并且动应力幅值过大时,刚开始振动试样就破坏,破坏形式为瞬时破坏。
Dynamic triaxial vibration test of unconsolidated and undrained geogrid reinforced clay. The test results show that the arrangement of grid reinforcement in clay soil can improve the dynamic shear strength of reinforced soil to a certain degree. The more reinforcement layers, the greater the dynamic strength of reinforced soil. The increase of geogrid The reinforcing effect of cohesive soil can be better exerted under high confining pressure. The increase of dynamic strength of reinforced soil is reflected in the increase of dynamic cohesion, but has almost no effect on the dynamic friction angle, and the number of cyclic loading vibration has little effect on the dynamic strength index. The dynamic stress amplitude for reinforced soil under cyclic loading The deformation is greatly affected. The deformation increases rapidly under cyclic loading with large dynamic stress amplitude, which can destroy the sample under the action of smaller vibration cycles. On the contrary, the sample with low dynamic stress amplitude needs to be Large vibration weeks to achieve the destruction of strain; reinforced soil there is a critical damage dynamic stress, when the set dynamic stress amplitude is less than the critical value, no matter how many times the vibration, the specimen failed to reach the failure strain; and dynamic stress amplitude When the value is too large, the sample just started to vibrate is destroyed, and the damage form is instantaneous damage.