Researches On 3D Numerical Simulation Of Improved Module Of Anti Slide Pile Types Based On Pile-Soil Interaction

Because of the huge economic loss and personnel injury caused by landslides, the anti slide pile is often used to reinforce slopes。At the same time,some new types of anti slide pile appear continuously. This paper summed up the danger and harmfulness of landslide and the research progress of anti sliding piles in landslide disaster. And then several problems for further research on anti slide pile design and calculation were pointed out and researched. In view of the complexity of soil-pile interaction which is difficult to be considered in the limit equilibrium calculation method often used in anti slide pile engineering,the reinforcement effect against different types of anti slide piles was simulated from the three-dimensional perspective using ABAQUS finite element software through project examples。The rules of stress and strain of anti slide piles and slope soils after the reinforcement are analyzed。Based on these the slide mechanism and reinforcement effect against different pile types were discussed。And then some innovative and useful conclusions which could provide theoretical basis and stress strain reference rules for the engineering design of anti slide pile were obtained。The main works and innovative conclusions are as follows:1、some simplified assumptions are always needed because of the difficulty to consider pile-soil interaction on the conventional design and calculation of anti slide pile. In this paper some key factors in design such as the soil pressure distribution pattern on pile、the soil displacement isoline characteristics around the pile、the relationship between slope stability coefficient and pile spacing、the disengaged deformation on the pile top、 the plastic deformation of slope、the internal force of pile、the displacement of pile etc are discussed with a three dimensional numerical analysis example of 1.5m × 2m square cross section pile(the diameter of corresponding equivalent circular cross-section pile is 1.96m)which is common used in practical engineering considering pile-soil interaction.2、The bending shear capacity of conventional anti slide pile is often insufficient when facing a landslide with massive earthwork、deep sliding surface、huge sliding force. When there is a structure such as a bridge of which displacement after work is strictly limited in the reinforcement rang and while the conventional “anti slide pile generally allows large deformations”,at this time even the pile bearing capacity can meet the requirement, it is difficult to meet the requirement of displacement tolerance after work. Focusing on these two problems mentioned above, attempts and efforts had been made to seek the new anti slide pile types with greater bearing capacity and smaller pile displacement based on practical engineering examples in this paper. Through 3D numerical simulation examples,the applicable advantages and applicable engineering environment for portal structure anti-slide pile、the relationship between portal structure anti-slide pile spacing and slope stability coefficient、the relationship between portal structure anti-slide pile spacing and stress or strain、the influence of beam structure stiffness on internal force of pile body had been discussed in detail.3、Compared with conventional large dimensional anti slide piles, anti-sliding micropiles have some incomparable advantages and have a better development in practical engineering. But there is not a mature, widely recognized design calculation theory because lacking of comprehensive understanding for the mechanism of anti slide micropiles.The influence of the diameter of micropiles, the angle between piles and potential slip surface, micropiles spacing, layout types of piles etc on slope reinforcement had been discussed through 3D numerical examples. And then through a sliding slope reinforcement engineering example on expressway, the good effect of anti-sliding micropiles used on some special cases in which the construction site and disturbance is limited and the construction period is very short has been verified.4、There is a very successful and mature development of prestressing technology in structural engineering. But in the geotechnical engineering of retaining structures, prestressing technology is rarely used. The use of prestressed technology of pile body which can improve the anti bending ability and reduce sliding pile section size is an issue worthy of attention.There is little research reference about this. Through 3D numerical simulation of prestressed reinforced concrete, the regularity of stress and strain distribution for piles、prestressed reinforcing bars、the main longitudinal reinforcement bars、hanger bars、compression side bars and the difference in slope stability between prestressed reinforced concrete anti slide piles and conventional reinforced concrete anti slide piles had been discussed according to the usual method of reinforcement bars in this paper.