Manufacture Of A Measuring System For Infiltration Characteristics Of Different Underlying Surfaces

In recent years,with the rapid development of cities,natural problems such as floods have become more and more serious.The number and scale of cities affected by floods in China have increased significantly,and the economy has been seriously damaged.The reason is that the construction of urban surface pipeline network facilities is seriously lagging behind the development of urban economy due to the increase of buildings and a large number of hard facilities.For the study of different pavement of roads and lawns,priority should be given to the limited rainwater to produce endless effect,more consideration should be given to the use of natural texture facilities to drain and build a new sponge city with natural accumulation,natural infiltration and natural purification.In order to measure the infiltration characteristics of different underlying surfaces,a system simulating the infiltration process was developed to measure the infiltration characteristics.The system consists of two parts:a rainfall generating device and an infiltration test box.The system can be used for water injection infiltration test and simulated rainfall infiltration test.In this experiment,the typical padding surface such as lawn,permeable brick pad surface and pebble pad surface were selected,and the bare soil pad surface was taken as the control test,10 cm as the test pad,and 50 cm test soil was taken as the infiltration layer.At the same time,the universal applicability of the system is verified by measuring the infiltration characteristics of three common cushion surfaces.In addition,the optimization comparison of the three cushion surfaces can be applied to engineering practice.Water injection test was used to simulate the urban water accumulation,and the water content and infiltration rate of several cushion surfaces are measured under the condition of water accumulation.The results show that the surface infiltration rate:turf cushion surface>permeable brick cushion surface>pebble cushion surface>bare soil,and the influence of cushion surface on comprehensive infiltration performance increases with the increase of depth.Rainfall condition（rainfall intensity is about20mm/h）.The water content and infiltration rate of several different cushion surfaces are measured during the rainfall process.The results show that the surface infiltration rate:turf cushion surface>permeable brick cushion surface>pebble cushion surface,and the saturated water content of the cushion surface are basically equal in the case of moderate rainfall,and the influence of the cushion surface on the comprehensive infiltration performance is considered.It decreases with increasing depth.From the analysis of water content change,the permeable brick pad is superior to the lawn pad and the pebble pad in water storage capacity,while the lawn pad is superior to the permeable brick pad and the pebble pad in water permeability.At the same time,the system defines the ratio of total saturated infiltration V and saturated time t as permeability i,which i as the analysis index to measure the infiltration characteristics of cushion surface.From data analysis,i_Lawn>i_{Permeable brick}>i_Pebble>i_{Bare soil}.