湿热地区路基湿度场分布与变化规律研究

发布时间：2018-04-05 11:04

本文选题：湿热地区　切入点：土水特征曲线　出处：《长沙理工大学》2015年硕士论文

【摘要】：湿热地区路基湿度受气候、地下水及路基路面排水等条件的影响,路基湿度随时间、空间变化,直接影响路基土体的刚度,甚至影响到路基路面的路用性能等。因而开展湿热地区路基湿度分布情况,制定有效的湿度稳定控制措施控制路基湿度变化,为湿热地区路基土湿度设计提供参考是十分有意义的。本文首先对湿热地区路基湿度的影响因素进行了分析,通过开挖路基断面,对断面路基湿度进行试验分析,结合对路基硬路肩下方湿度的研究,比较完整的得到了路基湿度的分布状况,并通过塑限对平衡湿度进行了拟合,得到了低液限黏土和含砂低液限黏土平衡湿度预测公式。通过对路基湿度的长期的观测,对路基土体内部的湿度和温度变化进行了分析,得到了路基湿度和温度的变化规律。这些结果为后面路基湿度模拟和路基湿度稳定控制技术提供了有利前提条件。通过对湿热地区低液限黏土和含砂低液限黏土路基湿度模拟参数试验和调查得到了路基湿度模拟所需的参数。对湿热地区两种土湿度模拟时土水特征曲线是否考虑竖向应力的影响进行了模拟对比分析,最后得出湿度模拟时土水特征曲线考虑竖向应力更符合实际。在此基础上进行了路基两种模型考虑土水特征曲线竖向应力分析,最后综合考虑,建议在路基湿度场模拟时,考虑竖向应力对土水特征曲线的影响,且应对边坡土体数值建模时进行平行于坡面分层。通过对路基湿度来源分析和含水率的入渗分析,得到了控制路基湿度的方法。对包边土进行了模拟分析得出渗透系数较小的黏性土包边对路基湿度的稳定控制具有很好的作用。对不同厚度砂垫层进行了模拟分析得到了砂垫层对于湿热地区降低路基水位和控制路基湿度稳定作用不大。
[Abstract]:The humidity of subgrade in humid and hot area is affected by climate, groundwater and drainage of roadbed and pavement. The change of subgrade humidity with time and space directly affects the stiffness of subgrade soil, even affects the road performance of roadbed and pavement.Therefore, it is very meaningful to develop the distribution of subgrade humidity in humid and hot areas, to establish effective humidity stability control measures to control the variation of subgrade humidity, and to provide a reference for the design of subgrade soil humidity in humid and hot areas.In this paper, the influencing factors of subgrade humidity in humid and hot areas are analyzed firstly. Through excavation of roadbed section, the moisture of section roadbed is tested and analyzed, combined with the research on the humidity of roadbed under hard kerb.The distribution of subgrade humidity is obtained completely, and the equilibrium humidity prediction formula of low liquid limit clay and sand containing low liquid limit clay is obtained by fitting the equilibrium humidity with plastic limit.Based on the long-term observation of subgrade humidity, the variation of moisture and temperature in subgrade soil is analyzed, and the variation law of subgrade humidity and temperature is obtained.These results provide a favorable precondition for the simulation of subgrade humidity and the control technology of roadbed humidity stability.The parameters needed for the simulation of subgrade humidity are obtained by testing and investigating the humidity simulation parameters of low liquid limit clay and sand containing low liquid limit clay subgrade in humid and hot areas.Whether the vertical stress is considered in the soil-water characteristic curve of two kinds of soil moisture simulation in humid and hot region is simulated and analyzed. Finally, it is concluded that the soil water characteristic curve in humidity simulation is more suitable for the vertical stress.On this basis, the vertical stress analysis of soil and water characteristic curve is carried out in two subgrade models. Finally, when considering comprehensively, it is suggested that the influence of vertical stress on soil water characteristic curve should be considered in the simulation of subgrade humidity field.And parallel to the slope surface stratification should be carried out in the numerical modeling of slope soil.The method of controlling subgrade humidity is obtained by analyzing the source of subgrade humidity and the infiltration of moisture content.Based on the simulation analysis of embankment soil, it is concluded that the clayey soil with small permeability coefficient has a good effect on the stability control of subgrade humidity.Through the simulation and analysis of sand cushion with different thickness, it is concluded that sand cushion has little effect on reducing the water level of roadbed and controlling the stability of subgrade humidity in humid and hot areas.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.1

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