Simulation Of Urban Underground Drainage Pipes’ Leakage And Development Of The Stainless Steel Sleeve

In recent years, problems of drainage pipes leakage in Chinese city become more and more serious. However, it’s very difficult to measure the rate of exfiltration and the rate of infiltration in the field. In this paper, the rules of exfiltration and infiltrating were studied through the self-made drainage pipes leakage simulation device and the stainless steel sleeve-one local repair technology focused on drainage pipes leakage was developed. The mechanical test and corrosion test for the stainless steel sleeve were conducted. Then the hydraulic loss and the effect of the stainless steel sleeve were conducted. Main results are as follows:(1)Three kinds of conditions test of exfiltration included clear water without buried soil, wastewater with buried sand and wastewater with buried clay. The rate of exfiltration were respectively5.67L-d-1·cm-2,1.33L·d-1·cm-2and0.67L·d-1·cm-2. Three kinds of water level of infiltration included150mm,200mm and250mm. And the rate of infiltration were respectively27.3L·d-1·cm-2、33.3L·d-1·cm-2�'�45.0L·d-1·cm-2.(2)The estimation method of exfiltration rate in the field was proposed. The rate of exfiltration of6km drainage pipes in District F in a south city ranged from15.0m3·a-1to981.6m3·a-1. The estimation method of infiltration rate in the field was proposed. The rate of infiltration of6km drainage pipes in District B in a southeast city ranged from832.2m3·a-1to4566.2m3·a-1.(3)The stainless steel sleeve was developed independently. And the mechanical properties of stainless steel sleeve were conducted through the mechanical test. It indicated that the loading capacity of2mm sleeve was3times of1mm sleeve, and it was better to place the stainless steel buckle on the top in the repair process.(4) The corrosion behavior of stainless steel201,304and316L were studied in the simulated drainage pipes reactor. It indicated that304and316L had much better corrosion resistance than201. And the service life of304and316L was more than80years, by contrast, the service life of201was less than10years.(5) The hydraulic loss of the stainless steel sleeve for drainage pipes was conducted. This paper chose a segment of50m DN300mm-pipe as an example to calculate the hydraulic loss. And it supposed that5sleeves embedding the drainage pipes were the limit. After calculating, the hydraulic loss increased by0.7%. In this case, the influence of the stainless steel sleeve embedding the drainage pipes could be ignored.(6)The repair effect of the stainless steel sleeve embedding the simulation device was studied. The repair rate could reach95%in the exfiltration test. And the repair rate could almost reach90%in the infiltration test. After the sleeves embedded the drainage, the rate of exfiltration of6km drainage pipes in District F in a south city ranged from0.75m3·a-1to49.1m3·a-1. After the sleeves embedded the drainage, the rate of infiltration of6km drainage pipes in District B in a southeast city ranged from99.8m3·a-1to547.9m3·a-1.