Conception And Model Test Of A New Support Type In Excavation Engineering

Under the dividend brought by reform and opening up,the process of urban modernization is accelerating.Many deep and large foundation pits are gradually appeared in geotechnical engineering field of vision.The deep foundation pit support is a temporary structure.And the purpose is to serve the construction of the main structure under the premise of ensuring the safety and reliability.Considering the existing supporting methods of foundation pit,the general ways to deal with deep and large foundation pit in our central city are mostly like internal support,pile anchor system and double row piles.These types of support have their own irreplaceable advantages,but they also have their own limitations.Nowadays,we advocate environmental protection,efficient and cost saving.It is imperative for us to improve the traditional support types,and constantly explore and propose new supporting forms to meet the needs of the design,construction and the whole environment of construction industry.Under such a trend and demand,this paper puts forward a new type of retaining structure--shear bond supporting system.The layout of the various parts of this specific ideas and detailed thought have been designed in tend to solve the existing problems of traditional support and to replace them in applicable conditions.After the shear bond structure is put forward,a model test of the new support structure is carried out according to the design type of the supporting pile in the actual project.The detailed test scheme was established.The traditional cantilever pile system and new shear bond system are compared in the same excavation work traits.We have explored and verified the excellent supporting effect of shear key structure from the displacement of pile top,the distribution law of bending moment of pile body,and the maximum bending moment of structure.Through the data obtained from the experiment,the working mechanism of the shear bond supporting system is explained to a certain extent.In order to provide more theoretical basis for future research,the paper also uses Midas GTS NX software to analyze the whole test process by finite element simulation.A more comprehensive exploration of the whole supporting effect is carried out.We can also explore the uplift and settlement law on top and bottom of supporting pit.It not only perfects the research of the model,but also validates and supplements the results of the experiment.The results of the test and finite element calculation show that under the same excavation conditions,the displacement of the new shear bond support system is smaller.The maximum bending moment of the pile is smaller.And the uplift value and the settlement value are less than the cantilever pile system.It means that the shear bond system has a greater support depth.In practical engineering,the design requirements can be met with smaller pile diameter and reinforcement,which is more safe and cost saving.At the end of this paper,the research work is summarized,and the future research direction is prospected.