Application Research Of Composite Support Technology Of Anchor Cable And SMW Pile

With the continuous advancement of urbanization in China,the development of foundation pit support technology for supporting the underground construction of various forms of structures has been promoted,especially in the past 30 years,the development of coastal cities has been extremely rapid,the introduction of SMW technology has provided strong technical support for the expansion of underground space in coastal areas,although the SMW method technology is relatively mature in design theory and construction technology,the application research of anchor cable and SMW method composite technology in Fuzhou area is less.Therefore,it is necessary to combine the engineering examples in Fuzhou to conduct research and analysis,thus providing valuable experience for the promotion of this technology in Fuzhou.Based on the foundation pit project of Geqiqunsheng resettlement house in Gaoxin District,the geological and hydrological conditions of the site survey and the surrounding environment,the supporting scheme of the foundation pit is in the form of composite support of anchor cable and SMW pile,through In-depth analysis of the theoretical calculation of anchor cable and SMW pile,further study on the deformation of deep foundation pits under the composite support form of anchor cable and SMW method,use the deep foundation pit software to carry out structural design verification,and combine the data obtained by finite element software simulation with the field measured data to verify the reliability of the model.the model is used to simulate the influence of different steel slab layout methods,prestressing values of anchor cables and additional loads on slope tops on deformation and internal forces of SMW piles.The main results are as follows:(1)According to the characteristics of the foundation pit project,the application of the anchor cable and the SMW pile composite structure in the project through the comparison of the schemes not only functions as retaining and stopping water,but also has the characteristics of easy construction and economy.(2)The typical 6-6 retaining sections of the foundation pit project are selected,and the supporting design calculation is carried out by using the deep foundation pit software.The maximum horizontal displacement value of the pile body appears at about 2m from the bottom of the pit,and the maximum displacement value is 24.59 mm.The curve shows a "C" shape,and the results of the safety and stability calculation of the foundation pit meet the requirements.(3)Simulated using Midas/GTS NX software,the farther the horizontal displacement value of the soil is,the more the value obtained from the pit is zero,the amount of bulge increases with the distance from the side wall of the foundation pit and then tends to be gentle,the settlement trend around the foundation pit shows a "concave" trough type,the maximum and minimum axial forces of the anchor cable appear on the free segment and the anchor segment respectively.(4)The pre-stress value of the anchor cable,the horizontal displacement value and the settlement value of the pile are compared with the monitoring values of the foundation pit,the trend is roughly the same,although there is still a small error between the two,the values are both within the allowable range,so the numerical simulation results are more reliable.(5)Through the single variable control method,the three factors of the layout distance of the steel,the prestress of the anchor cable and the load around the foundation pit are changed,the law of deformation and internal force of pile body can be obtained,analyze the simulation results,the reduction of the spacing of the steel strips makes the displacement and bending moment of the retaining piles smaller,the increase of the prestressing value of the anchor cable reduces the displacement value of the retaining pile and increases the bending moment value,the increase of the load value of the slope top will cause the displacement of the pile body and the value of the bending moment to increase,the displacement and bending moment curves under the three influencing factors respectively show a "spoon" shape and an inverse "S" shape.