摘要
为了研究土工格室加筋黄土的剪切性能,采用微型土工格室对不同加筋方式的格室加筋黄土及重塑黄土进行三轴剪切试验,得出加筋黄土及重塑黄土的应力-应变曲线及其抗剪强度指标,研究了加筋黄土和重塑黄土的应力-应变特性,分析了不同加筋方式下的加筋效果并讨论了不同土工格室层数加筋的加固机理。试验结果表明:重塑黄土和土工格栅加筋黄土的应力-应变曲线表现为弱硬化型,而土工格室加筋黄土的应力-应变曲线表现出明显的强硬化特性,4层土工格室加筋黄土的加筋效果最佳,2层土工格室加筋黄土在低围压、较大应变情况下,土工格室的加筋效果可以得到更好的发挥;重塑黄土和土工格栅加筋黄土的应力-应变曲线基本呈双曲线,用邓肯-张模型对其拟合效果很好,土工格室加筋黄土的应力-应变曲线用幂函数式对其逼近效果较好;土工格室加筋显著提高土体的摩擦角和黏聚力,2层土工格室加筋黄土的摩擦角和黏聚力相对重塑黄土分别提高38%和50%,4层土工格室加筋黄土的摩擦角和黏聚力相对重塑黄土分别提高63%和120%,均比土工格栅加筋黄土的高;土工格室的加筋效果优于土工格栅等平面筋材,且格室层数的增加能进一步提高黄土的剪切性能,其原因主要是土工格室"强化带"和"间接影响带"的存在,层数越多,"强化带"和"间接影响带"厚度越大,加筋黄土的抗剪强度会得到进一步提高。试验结果可为实际工程中设计参数的选取提供理论依据。
To investigate shear properties of geocell-reinforced loess,triaxial shear tests were conducted on compacted loess and geocell-reinforced loess with different patterns of reinforcement,by dint of the micro-geocell. The stress-strain curves and shear strength indexes of reinforced loess and compacted loess were obtained. Meanwhile,the stress-strain properties of reinforced loess and compacted loess were investigated. The effect of different reinforcement types was analyzed, and the mechanism of reinforcement with geocell under different layers was discussed. The results show that the stress-strain curves of compacted loess and reinforced loess with geogrid present slight strain-hardening behavior,while the stress-strain curves of geocell-reinforced loess present obvious strong strain-hardening behavior.The reinforcement effect of geocell with 4 layers is optimal,and the reinforcement effect of geocell with 2 layers can act well under the low confining pressure or the large strain. The stress-strain curves ofcompacted loess and reinforced loess with geogrid are hyperbolas. The fitting effect of such curves by dint of Duncan-Chang model is good. Furthermore,it is better to use power function type to fit the stressstrain curves of reinforced loess with geocell. The friction angle and cohesion of soil increase by the reinforcement with geocell,and the friction angle as well as cohesion of reinforced loess with geocell of 2 layers increases by 38% and 50%,compared with that of compacted loess respectively. Moreover,the friction angle and cohesion of reinforced loess with geocell of 4 layers increase by 63% and 120%respectively,which are higher than that of reinforced loess with geogrid. The reinforcement effect of geocell is better than that of geogrid,and the increase of the layer of geocell can further improve the shear property of loess on account of the existence of ＂enhanced zone＂and ＂indirect effect zone＂. The more the layers are,the larger the thickness of ＂enhanced zone＂and ＂indirect effect zone＂will be. The shear strength of reinforced loess will be improved as well. The results will provide the theoretical basis for the selection of design parameters in the practical engineering.
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2017年第10期17-24,共8页
China Journal of Highway and Transport
基金
国家自然科学基金项目(41272285)
甘肃省科技重大专项项目(1302GKDA009)
甘肃省交通运输厅科技项目(2017-002)
