Research On The Form Of Waterproofing And Drainage For Low Roadbed Of Oasis And Desert Highway In Xin Jiang Province

Due to the special topography and geomorphology and volatile climatic conditions，theseasonal rainstorms and melting snow prone to flood hazards of road in Xinjiang province，where are so many kilometers of embankment in highway that the road construction is of highcost and not harmony with the environment because of the code requirements and drainagesystem. In order to make the highway and environment more harmony, the author put forwardthe concept of low embankment, however, it is the decisive factors related to the stability ofhighway safety if highway roadbed protection and drainage system under low subgrade isreasonable.Therefore, the paper researched the form of protection and drainage facilitiesunder low embankment in Oasis and desert in Xinjiang province, the design has certainguiding significance to the protection and drainage facilities of new highway under lowroadbed. The specific contents are as follows:Through the investigation and analysis of natural environmental conditions and the usageof a number of existing roads’ protective drainage system,the paper summed up with betterdrainage facilities, drainage facilities which is destruction and the causes.At the same time,the paper analyses the applicability of the existing drainage facilities, provides practical basisfor engineering design of drainage facilities. In addition, the paper put forward the drainagestructure of porous culvert.The size of the porous culvert is determined by hydrological calculation.Hydrologicaldata can be obtained through the hydrological station, flood information and textual researchdata, through the analysis of flood frequency at single station and existing hydrologicalparameters variation,the paper introduces the curve fitting method, regional empirical formula,the inference formula and empirical formula which is used respectively in the areas with flowdata, the areas without hydrological data and the small watershed conditions.Hydrologicobservation data in relied engineering is relative lack, the varies in the interannual variabilityof the maximum flow of each river is inconformity and the gap is bigger, the coefficient ofvariation CVchanges from0.35to1.80, the CS/CVchanges from2.0to7.0. According to thehydrological parameters research of Xinjiang’s Highway, using the empirical formula issuitable for the projection of the design flow in the area, which offers the basic datas todeterming the size of the porous culverts.The flow capacity and ability to resist erosion of porous culvert is validated by thegeneralized hydraulic model test under design flow. Using a normality model test to observethe flow pattern and to measure the water level and velocity of each point on each section, which is done several times under the same conditions to ensure the accuracy of the test.Through the analysis of data and the drawing of line charts, it can be concluded that porousculvert can meet the requirements of flow capacity and ability to resist erosion.Combining with good drainage facilities in existing highway, according to thehydrological parameters calculation and hydraulic model test, the paper proposes designmethod of porous culverts and ancillary drainage forms that is suitable for the region of theoasis and the desert,which expects to give certain guiding significance to the reliedengineering and similar areas in design of drainage system under low embankment.