The Research Of TRD Method In Foundation Pit Support In The Yellow River Area

With the continuous expansion of urban scale and urban land supply constraints,high-rise buildings have been everywhere.Subway,corridor construction is also increasing,followed by deep foundation pit engineering is also more and more.TRD method is a new type of cement soil mixing wall construction method,through the study we can found that the method has a good water stop,the depth of uniform direction and so on,it has a good application prospect in the Yellow River alluvial plain.In this Paper,a deep foundation pit project of the Yellow River alluvial plain is taken as an example.The TRD method and the bored pile are used to calculate and analyze the force characteristics.The deformation of the wall subjected to TRD method is studied by different embedding depth,wall thickness and anchorage stiffness.Finally,the ABAQUS software is used to simulate the excavation of the foundation pit,and the stress and displacement characteristics of soil,wall and steel are studied.The main conclusions of this Paper are as follows:(1)TRD method can produce the wall with a good water stop,the depth of the wall uniform direction,equipment safety and so on.(2)Taking the deep foundation of the Yellow River alluvial plain as an example,the design method is used to calculate the results.The results show that the TRD method has high support and retaining effect.After excavation,Horizontal displacement is 2.87 mm smaller than that of bored pile,and the calculated settlement is 2mm smaller than that of bored pile.(3)Under the premise of satisfying the basic requirements of embedding depth,it is possible to reduce the settlement depth of the soil effectively,but the effect of reducing the settlement of the soil will be weakened when the limit is exceeded.Keep the TRD method in the same steel Parameters,the amount of change TRD method wall thickness,found in the wall of the moment of the wall,the shear force is mainly borne by the steel;Proper adjustment of the anchorage stiffness can effectively reduce the maximum bending moment and maximum shear force of the surrounding wall,and can also effectively reduce the surface subsidence of the soil around the foundation pit.(4)Using numerical simulation method to simulate and analyze a deep foundation pit project,the effect of excavation under different working conditions is studied.It is found that with the excavation of the foundation pit,the surface subsidence fluctuates around 4mm.The settlement of the surrounding soil mainly occurs above the maximum depth of the wall to the surface area of the soil.TRD method to support the maximum horizontal displacement of the wall occurred in the distance from the bottom of the site;The maximum stress value of steel support occurs in the middle of steel support,and the stress decreases with the decrease of the spacing between the side walls of the envelope.