固体废弃物填埋场传输线法渗漏检测定位研究

RESEARCH ON LEAKAGE POSITIONING METHOD OF SOLID WASTE LANDFILL BASED ON TRANSMISSION LINE METHOD

为解决新型无黏土层固体废弃物填埋场的渗漏检测问题,利用垃圾渗滤液会改变紧贴于膨润土防水毯(GCL)之上的导电纤维间分布电容与分布电导的基本原理,提出了基于传输线模型的渗漏检测定位方法。由于渗滤液会改变传输线电学参数进而实现渗漏检测,同时建立渗漏检测数学模型,依据传输线电报方程,推导出故障测距方程进行渗漏定位;分别从信号源频率、渗漏区域位置、导电纤维间距、终端电阻的选取,以及渗漏区域面积5个因素,分析了有无渗漏区域时终端电压幅值和相位的差异性;根据推导的测距方程,分别用牛顿算法和一般割线法计算渗漏区间坐标。实测结果表明:在其他因素相同的前提下,防渗膜的破损位置与检测结果高度吻合,一般割线算法求解非线性方程组的平均绝对误差为0.075,牛顿算法为0.135。因此,在渗漏检测定位中应选择精度较高的一般割线法,使得定位结果更加准确。

To solve the problem of leakage detection for a new type of solid waste landfill without clay,with the basic principle that landfill leachate will change the distributed capacitance and the distributed conductance of the conductive fibers,which cling to the top of the geosynthetic clay liner,a new method based on the theory of transmission line model was proposed for the detection and location of the leakage. It meant the leachate could change the electrical parameters of the transmission line,so that leakage detection could be realized. At the same time,the mathematical model of leakage detection was established,according to the telegraph equation of the transmission line to derive the equation of location and then to locate the leakage. The difference of terminal voltage amplitude and phase when leakage occured or not,was analyzed from five factors,such as signal source frequency,leakage location,spacing of conductive fibers,selection of terminal resistance,and size of the leaking area.According to the deduced location equation,the Newton algorithm and the general secant algorithm were used respectively,to calculate the coordinates of the leakage location. The results showed that the measurement result highly matched the position of breakage in impermeable membrane. Moreover,the average absolute error of the general secant algorithm for solving nonlinear equations was 0. 075,and the Newton algorithm was 0. 135. Therefore,the general secant method with high precision should be chosen in the leakage detection and location,which made the location result more accurate.