摘要
为了分析隐伏土洞演化对路基变形的影响,基于已有公路路基土洞的塌陷实例调研分析,提出土洞具有"圆柱状塌陷"及"漏斗状塌陷"2种演化模式;分别利用极限平衡理论和普氏平衡拱理论推导2种土洞演化模式的临界塌陷高度,结合FLAC3D软件分析土洞在演化过程中路基的变形及塌陷规律。研究结果表明:圆柱状土洞临界塌陷高度主要由覆盖土层强度、土体重度、土洞断面面积以及车辆附加荷载等因素决定;漏斗状土洞的临界塌陷高度主要由土体内摩擦角、土体坚固系数、初始土洞半径等因素决定;路基在土洞演化过程中经历稳定、基本稳定、临界塌陷及塌陷等过程;在路基土洞完全塌陷之前,路基表面的倾斜变形值超过允许标准值。
In order to analyze the influence of evolution of concealed soil cavity on the deformation of subgrade, two evolutionary models of "cylindrical collapse" and "funnel collapse" upward expansion of soil cave were proposed based on the analysis of the example of existing highway subgrade soil cave. The critical collapse height in the evolutionary models of soil cave was deduced by using the limit equilibrium theory and Platts equilibrium arch theory, respectively. The deformation and collapse law of the soil foundation in the course of evolution was analyzed by using FLAC3 Dsoftware. The results show the critical collapse height of cylindrical shaped soil cave is mainly determined by the factors such as the strength of the covering soil layer, the soil mass, the section size of the tunnel and the additional load of the vehicle. The critical collapse height of funnel shaped soil cave is mainly determined by the factors such as the friction angle of soil, the coefficient of soil firmness, the radius of initial soil cave, and so on. In the course of the evolution of the soil cave, the subgrade undergoes the process of stability, basic stability, critical collapse and collapse. Before the collapse of the subgrade soil cave, the slope deformation of the subgrade surface will exceed the allowable standard value after stabilization.
引文
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