Research On The Mutual Influence And Design Optimization Of Anti-slide Pile Support For Slope Foundation Pit

The construction on slope is especially common in mountainous cities in China.Because of the scarcity of urban land resources and the limitation of red lines on the land,the foundation pit projects are very close to the foot of the slope.The excavation of the foundation pit will weaken the lateral restraint of the slope,which will lead to deformation and destruction of the slope and threaten the safety of the foundation pit project.How to ensure the safety of slopes and foundation pits on slope is a theoretical and technical issue that geotechnical industries must face.The slope and the foundation pit are a unified system of interaction.When the excavation edge of the foundation pit is close to the horizontal distance of the slope foot and the depth of the foundation pit is large,the excavation of the foundation pit will have an adverse effect on the deformation and stability of the slope,resulting in excessive deformation of the slope,even severe ones will lead to instability in the slope and deep foundation pits,causing major accidents.Therefore,the mutual influence between the slope and the foundation pit cannot be ignored.In the actual engineering design analysis,the two must be taken into consideration as a whole for a joint action,so as to ensure the stability of the slope and the safety during the construction of the pit.In the process of designing and excavating the foundation pit,the stability of the foundation pit must be ensured,and the influence of the slope on the deformation and stability of the foundation pit must be taken into account.At this time,whether the safety distances of foundation pits and slopes are adequate and the choice of support type is particularly important,which will concern the success of the design and the safety and reliability of the construction process of the foundation pit.In order to ensure the safety of slopes and foundation pits,it is imperative to begin the work of “exploring the mutual influence and optimization of anti-sliding piles in foundation pits”.Based on the above considerations,the finite element numerical analysis software Midas GTS NX was used to establish a two-dimensional model of the slope foundation pit.Based on the above considerations,the finite element numerical analysis software Midas GTS NX was used to establish a two-dimensional model of the slope foundation pit.By changing the horizontal distance of the pit from the foot of the slope,the change of the stability coefficient of the two as a whole at different distances from the foot to the foot of the foundation pit is analyzed,and the displacement of the top of the pile after supporting the anti-sliding pile respectively is analyzed.The three distances are respectively supported by different lengths of piles,and the law of the stability of the two as a whole changes with the change of the distance between the two,and the distance between the two can be used as a single individual to analyze and support the distance,revealing Both of them adopt the mutual influence mechanism of anti-slide pile support.The above-mentioned theoretical analysis results were specifically applied to the "Foundation Pit Support Project of Huma Mountain in Knuming" for verification.Through the analysis and demonstration of actual engineering,the optimal support design scheme is sought.The conclusion of this study has certain reference significance for the support design of similar foundation pits.The following conclusions are drawn through the study:(1)When the pit and the slope are close to each other,there is a problem of mutual influence,and this problem can not be ignored;(2)Before foundation pits and slopes are not supported,when the horizontal distance between the foundation pit and the slope is below 18m(excluding 18m),there is a potential slippage between them as a whole;When the horizontal distance between the two reaches 18 m,there will be no mutual influence between the two,and L=18m is the distance limit between the two.(3)When the foundation pit and slope are supported by piles respectively,when L ≥ 12 m,the displacement of the pile top of the two piles is almost 0,which means that the mutual influence of the support of the anti-slide piles will be weakened greatly until it disappears.(4)When the foundation pit and slope are relatively close to each other,in order to avoid mutual influence between the two,anti-slide piles can be installed on the slope for one-time support.In this case,the total height of the composite slope formed by the foundation pit and the slope should be fully considered to design the anti-slide pile to be long enough.(5)After optimization of support design,anti-slide piles at the slope can be used as the retaining structure of the slope to ensure the stability of the slope,and can also be used as the retaining structure of the foundation pit to ensure the safety of the foundation pit construction,achieving the "two use" effect.(6)When the pile and anchor are combined and supported,the displacement of the pile top is the minimum and the supporting effect is optimal under the condition that the anchor cable inclination angle is 15°.