路基土回弹模量湿度调整系数预估研究

Study on Moisture Adjustment Factor for Resilient Modulus of Subgrade

摘要:

选取了几种代表性的路基土样,采用UTM(万能材料试验机)动力三轴试验系统,测试不同湿度下的回弹模量,分析湿度对路基土回弹模量的影响规律,利用测试结果,对Witczak回弹模量湿度调整系数模型中的参数进行校正,建立适用于我国粗细粒土组的湿度调整系数预估模型.结果表明,路基土湿度在最佳含水率饱和度±20%区间内,模量调整系数与饱和度差值近似呈线性关系,而当湿度低于最佳含水率饱和度20%以上时,模量调整系数受饱和度变化的影响很小.针对不同类型土组,应用建立的模型,推荐了回弹模量的湿度调整系数,可结合室内回弹模量测试,反算路基在实际湿度状况下的回弹模量值.

Abstract:

Several types of subgrade soil were sampled,and resilient modulus of subgrade soil with different moisture were measured using UTM dynamic triaxial test symtems.The effect of moisture on resilient modulus was analyzed and parameter calibration was executed on Witczak model of moisture adjustment factor for resilient modulus,furthermore,the model of moisture adjustment for resilient modulus applicable to coarse and fine grained soil in China was established.The results indicate that moisture adjustment factor varies linearly with moisture difference value which is in the range of -20%～20%,and moisture adjustment factor is not affected significantly by moisture difference value which exceeds 20%.Using the established model,the moisture adjustment factors for different types of subgrade soil are recommended,which can be used to predict field resilient modulus of subgrade soil with real moisture content combined with resilient modulus test in laboratory.