不同相对密实度下砂土侵蚀破坏试验研究

Experimental study on erosion and destruction of sandy soil under different relative compactness

水力管线渗漏诱发城市地面塌陷灾害具有突发性、复杂性和高危害性的特点,对砂土在不同相对密实度侵蚀破坏过程进行试验研究可为灾前预防和灾后处理提供参考依据。文章设计了一种砂水流失可视化试验系统装置,采用数字照相量测技术对试验数据进行处理,运用图像分析法分析了砂土侵蚀过程,通过拟合法和理论分析法研究了砂土侵蚀破坏范围与砂土特性之间的关系。结果表明:砂土侵蚀发展过程分为渗水微流砂、砂水流失耦合加剧和弱流水少砂趋稳等3个阶段;砂体侵蚀过程可划分为塌落、流动、随动和稳定4个区域,流动区和随动区之间的破坏曲线呈二次抛物线形状;砂土流失量与破损口面积、水力梯度和侵蚀时间呈正相关,与破损口周长呈负相关。

The urban ground collapse disaster induced by hydraulic pipeline leakage has the characteristics of sudden,complexity and high hazard.The experimental study on the erosion and destruction process of sand with different relative compactness can provide reference basis for pre-disaster prevention and post disaster treatment.In this paper,a visual test system device for sand water loss is designed,the test data are processed by digital photogrammetry technology,the sandy erosion process is analyzed by image analysis method,and the relationship between sandy erosion damage range and sand soil characteristics is studied by fitting method and theoretical analysis method.The results show that the development process of sand erosion can be divided into three stages:seepage micro flow sand,coupling intensification of sand water loss and stabilization of weak flow and less sand.The erosion process of sand body is divided into four areas,including collapse,flow,follow-up and stability.The failure curve between the flow area and follow-up area is in the shape of quadratic parabola.The amount of sand loss is positively correlated with the area of the damaged mouth,hydraulic gradient and erosion time,and negatively correlated with the perimeter of the damaged mouth.