一种新型排水结构的排水性能试验研究

Drainage Performance Tests of a New Drainage Structure

目前边坡和支挡工程中最常用的排水结构(PVC排水管)服役一定年限后,易发生堵塞,排水功能失效。为研究一种排水效率高、不易堵塞的新型排水结构(排水钉),在室内开展了历时4个月的PVC排水管和排水钉的排水对比试验,系统研究两者的排水性能和抗淤堵性能;同时开展排水钉设置间距和设置长度对自身排水性能的影响试验,并分析排水钉的反滤机制。结果表明:排水钉能持续保持良好的排水性能,而PVC排水管排水性能则逐渐下降,包裹PVC排水管的土工布发生了一定程度的淤堵,使流速最大降幅达35%;砂土中排水钉的有效排水半径约为1.0 m,排水钉置入边坡应穿过最危险滑动面至少1.5 m;排水钉周围形成天然的反滤层,能发挥排水、挡土和防淤堵的作用。

The PVC pipe is most commonly used for drainage purpose in slopes and retaining walls. However, clogging is a main issue after the pipe is put into service for some years. In this study, a new type of clogging-free drainage structure with highly efficient drainage, was investigated. A series of laboratory tests were performed to evaluate the effect of installed spacing and installed length on the new drainage structure. The performance of anti-clogging was also evaluated. After that, the long-term performance of the PVC pipe and the new drainage structure under wetting-drying cycles was also carried out and compared. The results show that in the sand, the drainage performance of the new drainage structure is efficient, while the drainage performance of the PVC pipe decreases gradually. The woven geotextile wrapping the PVC pipe is clogging to a certain extent, which makes the flow rate decrease up to 35%. The effective drainage radius of the new drainage structure is 1.0 m. The installed length with at least of 1.5 m that passes through the most dangerous sliding surface is recommended for this new drainage structure when it is installed in slopes. Moreover, the new drainage structure causes the formation of a natural filter layer around the external surface, which can play a part in drainage, retaining soil and anti-clogging.