尺寸效应和约束条件对土基回弹模量的影响

室内承载板法是测定土基回弹模量的标准试验方法。尺寸效应和约束条件的影响使得室内测定的回弹模量往往与现场不符,不能直接用于公路结构设计。以红黏土为研究对象,采用室内试验和数值模拟的方法研究了试样的尺寸效应和约束条件对土基回弹模量的影响。结果表明:试样的尺寸效应(试样直径和高度)对回弹模量的影响较大,随着试样直径的增大回弹模量增大,随着试样高度的增大回弹模量减小;无侧限条件下测定的回弹模量乘以约束条件系数1.2即得有侧限条件下回弹模量值。研究成果为室内合理测定土基回弹模量值提供参考依据。

Influences of Size Effects and Constraints on the Rebound Modulus of Subgrade

Indoor bearing plate method is the standard test method to determine soil resilient modulus.The influences of size effect and constraint condition make the rebound modulus in the laboratory inconsistent with the field,which means it cannot be used directly in the highway structure design.With red clay as the research object,this paper studied the size effect and constraint conditions of sample on the subgrade resilient modulus by means of laboratory and numerical simulation.The results show that the size effect of specimen (specimen diameter and height) has great influence on the modulus of elasticity.With the increase of specimen diameter,the rebound modulus increases,and the rebound modulus decreases with the increase of specimen height.Under the condition of no limit condition,the modulus of elasticity is determined by multiplying the modulus of elasticity under the condition of 1.2.The results could provide reference for the reasonable determination of rebound modulus of subgrade.