坡面径流实时监测装置研究与应用

Study and Application for Real Time Monitoring Device of Slope Runoff

径流泥沙含量测量是准确计算土壤流失量、科学评估水土保持效益的关键工作,也是水土保持监测的主要技术瓶颈之一。研发实现径流泥沙含量的实时动态监测设备对提高水土保持监测工作效率、促进水土保持行业发展具有重要意义。本文介绍了“坡面径流实时监测装置”的测量原理及其核心构件,完成了“坡面径流实时监测装置”的室内清水检测试验,跟踪了系统修正后的野外应用效果。得到如下结论:(1)坡面径流实时监测装置以集流桶、超声波液位传感器、重量传感器、电动阀、下位机和上位机为核心组件组成,其部分测量误差来源包括液位测量误差、泥沙比重误差及水流冲击力误差;(2)液位测量误差与集流桶横截面半径d(m)密切相关,主要体现在对径流总体的测量偏差,最小偏差为0.196d2,通过减少集流桶横截面半径,能够有效减少液位测量误差;(3)泥沙比重误差随被测泥沙比重的增加而减少,当被测泥沙比重在2.0—2.4范围内且每偏差0.01时,对泥沙含量测量的偏差均小于0.01(m总—V总·ρ清);(4)水流冲击力误差会导致液位在较低水平时测量精度较差,通过降低径流跌落高度能够有效减少误差;(5)通过定型设计与理论公式的优化,坡面径流实时监测装置的最小测量偏差可达±6.7%。

Measuring the sand content of runoff is key work in precisely calculating quantity of soil loss and scientifically evaluating the benefit of water and soil conservation,also is one of the technical bottlenecks in monitoring water and soil conservation.It is an important work to study the device and realize real time monitoring in improving work efficiency of water and soil conservation monitoring and promoting professional development of water and soil conservation.In this paper,the author presenting measuring theory and its key parts for the real time monitoring device of slope runoff,completed the clear water testing experiment in door for the real time monitoring device of slope runoff,and followed the tracks of field application effect after the system corrected.The following results are obtained:·The key parts of real time monitoring device of slope runoff are composed of runoff collecting tank,supersonic wave liquid level sensor,weight sensor,electrical operating valve,lower computer and upper computer,and its measuring error partly consists of liquid level measuring error,sand specific gravity error and flow impact force error.·The liquid level measuring error is closely related to cross section radius d(m)of runoff collecting tank,mainly reflecting in total runoff measuring error,and minimum error is 0.196d2.By reducing the cross section radius of runoff collecting tank,the liquid level measuring error can be effectively reduced.·The sand specific gravity error is reduced with sand specific gravity measured increasing.When the sand specific gravity measured is in region 2.0-2.4,and when each error is 0.01,sand content measuring error are all less than 0.01(m总—V总·ρ清).·The flow impact force error can result in relatively bad measuring accuracy when the liquid level is relative low.By decreasing drop height of runoff,the error can be effectively reduced.·By means of typical design and optimizing theory formula,minimum measuring error of real time monitoring device of slope runoff is±6.7%.