旱地水窑开挖数值模拟与结构形状参数验证

Numerical simulation of water kiln excavation and verification of its shape parameters

旱地水窑是集雨蓄水,解决人畜饮水、发展节水灌溉的有效集雨蓄水工程。从水窑结构受力特性分析,水窑属于浅埋式非衬砌地下结构,其结构形状及尺寸是决定窑体稳定和安全的关键因素,而开挖阶段又是窑体最危险阶段之一。针对前期研究所拟定出的斜墙圆拱式窑体形状及参数,应用弹塑性非线性分析方法,分别采用两种不同开挖工序及过程进行开挖过程模拟研究,并从反映水窑体稳定性的位移、塑性区及拉应力3个方面分析了开挖卸荷对窑体稳定性的影响。数值模拟结果表明:不管采用上行法还是下行法开挖,水窑在开挖过程中土体是稳定的,从而验证了以前研究所推荐的水窑形状参数及拱曲线是合理的,所提出的计算理论和方法可以用于实际水窑的设计。

Water kiln is a kind of catchments and conservancy project to retain rainfall so as to meet the needs of human beings, animals and saved irrigation..It belongs to a special underground structure with small depth of burial and without liner based on its mechanical characteristics. The stability and safety of kiln is determined by its structure shape and shape parameters. The excavation stage is one of hazardous stages due to construction perturbation and unloading of surrounding kiln soil body. The excavation process was divided into upward and downward excavation methods. Using nonlinear clasto-plastic analysis method, the excavation process of practical water kiln designed was simulated according to the shape and parameters of inclined-wall round-arched kiln determined by primary research. Effects of excavation loads on the stability of kiln were analyzed from three aspects of displacements, plastic zones and soil tensile stresses. The numerical simulation results show that the soil body of water kiln is stable in spite of upward or downward excavation method. The rationality of water kiln shape parameters and arch curve equation proposed by primary research are validated and its calculation theory and method can be applied to the design of water kiln.