Study On Directional/Guided Drilling Of Trenchless In Fluvial Facies Stratum

Trenchless-guided drilling technology, which is, as a new pipelaying method, environment-protective, efficient and energy-saving, has been widely accepted gradually, and moreover, has been recognized as a most promising branch of construction industry. In this thesis, the author takes both an academic and a practical way to study the key technology of trenchless-guided drilling and construction in the typical fluvial facies conditions, according to the analysis of typical fluvial facies stratum and terra conditions. The specific contents are as follows:1. This thesis makes a profound study of the reasons why the hole wall is not that strong when trenchless-guided drilling technology is adopted under scree environment. The author introduces slip-casting pretreatment technology to enhance the stability of the hole wall in hardpan condition.2. Through the analysis of functions of drilling mud such as leveling off hole wall, schlepping sludge, lubrication and drag reduction of slurry in the process of trenchless-guided drilling and construction, the author brings forward the special slurry recipe for hardpan's trenchless-guided drilling after slip-casting pretreatment, and the slurry formula for the purpose of lubrication and drag reduction in the drilling process of terrane or hardpan.3. The author advances of impacting gyration drilling+reverse Expander as the preferred choice in hard rock stratum constructions, and furthermore, optimize this techniques and introduces the best method for the optimum selection of construction parameters in different stratum conditions;4. The author analyses the relevant factors which may influence guided tract, and advances the relevant improving measures.5. Using for reference calculation of the earth pressure, the author suggests a calculation method of pipe and canal return-pull power in fluvial facies stratum, which offers gist for choosing parameters in trenchless-guided drilling and spreading pipe technology.6. The author analyses the typical trenchless-guided drilling cases under fluvial facies stratum condition, discusses this kind of river traversing techniques in detail, and makes a deep research into the causes of usual accidents, such as, the departure of guiding tract from designed tract, the fall or breaking off of drill stems or drill tools, blocking of niping drill, pneumatic hammer, aiguille, etc. in the process of guided drilling or hole expanding, and hereby advances corresponding measures for prevention and management of these accidents.