Research On The Prevention Engineering Of Micropile For Landslides Triggered By Wenchuan Earthquake

Micropile has been used in landslide reinforcement more and more popular, especially used in rescuing project because of the merits:little machinery; adaptability to stratum; little vibration and low noise; low influence to the landslide; various layout mode; rapid constructing speed. Although micropile technology put into use in engineering is more popular, its deformation characteristics have not been fully understood, its design calculation theory methods are short of enough engineering examples and systemic engineering inspection because of its short application time.Based on China Geological Survey item "Large scale model text on micropiles in landslide reinforcement" and phoenix landslide prevention engineering for micropile, through the interior of physical model experiment, the detailed investigation, numerical analysis and field engineering practice method and means, the following aspects are systematically studied:(1) Using trough, drilling, pitting and geophysical exploration methods of such detailed investigation, the potential sliding surface of phoenix mountain landslides is confirmed, and its stability is calculated and analyzed.(2) Through various treatment solutions for phoenix landslide, the final solution for management is established.(3) Based on "Large scale model text on micropiles in landslide reinforcement", failure mode and rule for its stress and strain of micropile are detailedly studied. According to the result of excavation, failure mode and strain of micropile are analyzed. Rule for its stress is summarized based on the results, and curves of "P-y" are drew, fitting formulas are provided subsequently.(4) By real-time monitoring for soil pressure, changing processes for micropile referred to thrusting force of pile and soil resistance of the body are acquired.(5) According to results of surface displacement control engineering for phoenix mountain landslide, surface deflection for prevention engineering of micropile is studied. (6) Comparative analyses between the results from monitoring for soil pressure and from surface displacement control engineering are studied, and effectes of prevention engineering of micropile are verified.Through the above content of study, this paper mainly made the following results:(1) Deformation and failure mechanism of micropile are systematically analyzed. Distribution pattern for thrust of micropiles is acquired, bending and shearing curves are drew, fitting formulas for stress and strain are provided.(2) Real-time processes for stress and deformation of micropile in phoenix landslide are got. Stability for phoenix landslide with micropiles is calculated combining with the results from monitoring of surface displacement control engineering.(3) An example for shattering mountain prevention with micropile is established. Through the results from "Large scale model text on micropiles in landslide reinforcement" and phoenix landslide prevention engineering for micropile, successful experience from which landslide with micropile can be more stable will provide an example for other seismic landslides and other type landslides.