The Research Of Supporting Parameters Optimization And Ultimate Displacement Of Extra-long Anti Slide Pile Wall In Deep Landslide

Since the implementation of reform and opening-up policy, economy in our country hasdeveloped rapidly, which make it possible to develop civil engineering under specialgeographical conditions so that a lot of railway, highway and underground engineeringconstructions have sprung up. However, constructions in landslide area always causegeological disasters which menace to constructors’ lives and delay constructions. Consideringthe mentioned conditions, the anti-pile becomes a quite favored tool and plays anirreplaceable role in civil engineering with such advantages as strong anti-slide force, simpleequipment, efficiency of engineering, low noise and easy operation. Since the anti-slide pileused in underground construction, it is quiet necessary to set the retaining wall―the wall ofanti-slide pile during construction in order to ensure the safety of workers and progress ofconstruction. Once the anti-slide begins to operate, the retaining walls, as the main support ofthe free surfaces, will under soil pressure generated from nearby rocks. So far, there is neitherscientific proof that can be used to prove the relationship between the excavation depth ofanti-slide pile and lateral earth pressure, nor obvious considerations upon the contributionmade by the retaining wall to the bearing capacity of pile have been taken in the design ofanti-slide pile. However, the scientific and reasonable design of the anti-slide pile has a directeffect on the safety of construction personnel and engineering quality of anti-slide pile.At present, there is almost no similar engineering both at home and abroad for referencein the excavation of anti-slide pile more than70m―a particular long anti-slide pile. In orderto study the ultimate displacement of the anti-slide pile wall of deep landslide, based on theDaping Landslide Treatment Engineering, this thesis make a numerical simulation analysisabout the stress and deformation of anti-slide pile at70-71m with the help of the large-scalefinite element software ANSYS. Relationship between the stress release rate and the plasticstrain is established based on Rankine Active Earth Pressure Theory and the Soil ArchingEffect Theory. According to the plastic strain mutation theory, I find the correspondingdisplacement produced by the plastic strain mutation is the ultimate displacement of theanti-slide pile wall, and I also optimize the supporting parameters of anti-slide pile wall.The main contents and methods:(1) Having looked up a large number of literature data, I have a new understanding ofdeformation of surrounding rock mass nearby anti-slide piles. The deformation of surroundingrock mass nearby pile refers that once the anti-slide pile excavation started, its support,namely, the anti-slide pile retaining wall will plastically deformed, and this deformationcannot be effectively controlled so that the deformation value is greater than the specified value. Or, it can be regarded as the deformation of surrounding rock masses according tocracks and summons around anti-slide pile after the completion of the anti-slide pile.(2) The pile surrounding rock mutations in the state of the plastic strain is defined as thelimit state. By simulation of the surrounding rock stress release, namely, in the change ofsurrounding rock stress release rate, the plastic strain at the key point of pile surrounding rockmutated and come to limit state. Drawing curves of key plastic strain and displacement of keypositions change with stress release rate with Excel, plastic point mutation is presented, basedon which, the limit value of deep landslide specialty of anti-slide pile retaining walldisplacement will be calculated.(3)When making a numerical stimulation of several elements which affect the strengthof the surrounding rock stability, analysis must be based on other parameters as constantvalue and change a parameter to study its influence in the trend of the plastic strain anddisplacement and stress changes so as to optimize the supporting parameters of the anti-slidepile wall.The main achievements include:(1) Combined with the situation of Dapping Landslide and based on the spatial effects inthe excavation process of the pile, I sum up some reasons for the rock deformation around thepile. The internal reason is ohtsubo landslide geological characteristics, namely thecharacteristics of rocks of soil Zhou Yan anti-slide piles and pile in high ground stress; theexternal reasons include construction technique and the anti-slide pile supporting andprotecting measures, etc.(2) Guided by the plastic mutation theory, I use large finite element software ANSYS tomake the numerical simulation and Excel to draw curve to get plastic mutation point andfinally I get the ultimate displacement value of deep landslide extra-long anti-slide pile wall:1.04mm for the top foot;3.53mm for midpoint of X direction and3.12mm for the midpoint ofY direction.(3) By making numerical simulation about the anti-slide pile in different supportparameters (different elastic modulus and different thickness), I make some optimizations ofanti-slide pile wall’s supporting parameters. It is suggested that elastic modulus value ofthe anti-slide pile is E=2.8e10N/m2, to be specific, the wall is consist of C20steel reinforcedconcrete, the wall reinforcement include44Φ12main reinforcements and8Φ12framereinforcements, the length of each main reinforcement and each frame reinforcement is1.3meters and15.486meters respectively and the thickness of anti-slide pile wall is0.50meters.