发泡颗粒混合轻量土抗剪强度特性试验研究

Experimental Study on the Shear Strength Characteristics of Foamed Particle Light Weight Soil

通过三轴试验对发泡颗粒混合轻量土抗剪强度特性进行了研究.结果表明:剪胀条件下轻量土的峰值主应力差早于最大有效主应力比到达或者二者同时到达,剪缩条件下二者则同时到达.应力-应变曲线的软化与硬化是剪胀剪缩的外在表现,软化型宜采用峰值主应力差标准,硬化型采用轴向应变15%标准.破坏包线有直线型与折线型,包线形态受配比与围压控制.黏聚力、有效黏聚力随EPS颗粒掺入比增大而减小,随水泥掺入比增大而增大;内摩擦角、有效内摩擦角随EPS颗粒掺入比增大而减小,随水泥掺入比增大没有显著变化规律,介于6.0°～13.0°.低围压,试样破坏形态为鼓型,出现剪切带,反之为收缩型,不出现剪切带.

The shear strength characteristics of foamed particle light weight soil were studied by triaxial compression tests.The results show that the peak principal stress difference is reached earlier than the maximum effective principal stress ratio,or that both occur simultaneously under shear dilatancy condition.The two standards reach the maximum at the same time under shear contraction condition for light weight soil.Strain softening and strain hardening are an external behavior of shear dilatancy-contraction.The softening condition is fit using the peak principal stress difference as the standard.The hardening condition is fit using the axial strain （15%） as the standard.There are two types of failure envelops：beeline and broken line.The envelope shape is determined by the mixing ratio and the confining pressure.Cohesion and effective cohesion decrease with an increase in the ratio of EPS particles.They increase with an increase in cement content.The internal friction angle and effective internal friction angle decrease as the ratio of EPS particles increases,but there is no significant change （6.0°〈φ〈13.0°） as the ratio of cement is increased.The failure shape of the soil sample is in the form of a drum under low confining pressure and a shear zone is observed.On the contrary,the failure shape is a contraction without a shear zone.