Research On The Clogging Mechanism And Anti-siltation Technology Of The Incline Drainage Hole On The Cutting Slope

With the increase of the operation time of various geotechnical engineering,the phenomenon of drainage hole clogging in the construction of the project has become more and more obvious.The smooth drainage of the drainage holes has a very important impact on the safety and stability of the project.Studying the drainage hole clogging mechanism and anti-sludge technology is the key to solving this problem.Based on the highway slope drainage hole engineering,this paper studies the clogging mechanism and anti-sludge technology of slope inclined drainage hole by field geological survey,data analyzing,physical and chemical test analysis,model test and field engineering application.(1)The traditional geotextile wrapped drainage pipes and soft drainage pipes on the slope of the field area are more severely blocked,and their suitability is poor.The mechanical clogging is mainly caused by mud blocking in the hole,and the clogging of the slope mainly composed of fine granular soil is often more serious.The chemical clogging is mainly manifested as the soft slag of the soft drain pipe is easy to form a chemical clogging mainly composed of iron.In the limestone area,the chemical clogging phenomenon mainly consists of calcium deposits.It is characterized by a layer of calcium carbonate crystals adhering to the surface of the fiber.Calcium chemical clogging can be acid cleaned as well as iron chemical clogging,but the acidity should be determined according to field conditions.Biological clogging is mainly characterized by traces of biological activities such as fungi,algae,and moss,and vegetation develops after severe clogging.(2)The indoor model test can better simulate different slope conditions,changes in groundwater level,intermittent drainage and other conditions by configuring soils with different permeability coefficients and changing the water head in the model box.The test results show that the soil permeability coefficient and the size of the outer casing affect the displacement of the drainage hole,and the permeability coefficient of the infiltration soil has a greater influence on the displacement.The anti-clogging drainage hole has stronger adaptability to different soils.(3)Through on-site investigation and comprehensive analysis of various physical and chemical tests and simulation tests,drainage hole clogging can be divided into two typical stages: at the beginning of the layout,mechanical clogging is the main feature,which means that the fine-grained soil moves to the periphery of the drainage hole to form a clogging;with the increase of operation time,affected by on-site geological conditions,chemical clogging and biological clogging become more and more obvious.Chemical crystals and biological clogging make the clogging materials stick together to make the clogging and the outer covering better.The whole,eventually developed into a three-dimensional comprehensive clogging.(4)The small aperture is an important reason for the fast blocking speed of the outer covering.The screen has a larger hole diameter than the geotextile.At the same time,the screen has a single-layer structure,and it is difficult to form a three-dimensional clogging relative to the geotextile;therefore,under the same conditions,the screen clogging cycle It has a longer clogging cycle than geotextiles and is easier to clean.(5)Through chemical clogging test and indoor model test,it is determined that the anti-clogging drainage hole drainage capacity and anti-clogging ability are better than the traditional drainage holes.Moreover,the double drain hole also has the advantage of being more convenient to clean and replaceable.(6)The anti-clogging drainage hole has good drainage in the operation of the original typical silt slope,and has the advantages of simple construction,convenient disassembly and washability,and reusability.At the same time,no obvious clogging phenomenon is found in the on-site operation,but its operation time in the actual project is better.Short,field trials also require longer time to verify and improve.