Study On Frozen Reinforcement Mode Of Rich Sand Layer In Zhengzhou Region

Artificial frozen method has been widely used in the construction of contact channels because of its green and non-pollution characteristics.Different in the frozen method,natural factors and human construction factors have different effects on temperature field development,and improper treatment can cause the freezing wall to generate unhaneously or overfront;the freezing contact channel is easily caused by excavation.The surface displacement thus has an impact on the peripheral line and surface building.Based on the above problems,this paper is based on Zhengzhou Airport to Xuchang City,Zhengzhou Section,and the interior test,theoretical derivation,numerical simulation and on-site measurement method,systematically research at the rich sand layer The contact channel in the frozen method,the changes in temperature field,seepage field,and stress field during the construction process of frozen method,the main research content and the conclusions are as follows:(1)Under low temperature conditions,a single-axis compression test is performed on site-collected soil samples,single-axis flap test,three-axis shear test,to obtain its-10 °C compressive strength of 4.43 MPa,elastic modulus It was 99.53 MPa,the Poisson ratio was 0.256;the anti-compensation strength(bending strength)was 2.25 MPa;the adhesion was 1.177 MPa,the inner friction angle was 21.86°.(2)Based on the test result,combined with the actual conditions,the structure mechanical method is used to detect the thickness design of the frozen wall through numerical simulation,and the results show that the contact channel is buried in the area of rich sand in the region.When the thickness is less than 14.55 m,the thickness of 2 m can meet the strength requirements.(3)Based on the flow heat coupling theory,combined with the actual working condition simulates the change of temperature field during the freezing process and compared with the on-site measurement,the method of sensitivity analysis is used to study different factors on the development of temperature field development on the basis of this model.The results show that the influence of four factors on the frozen temperature field is from large to small,the frozen tube spacing,the diameter of the frozen tube,the freezer diameter,the initial land temperature,based on this proposal to reduce the freezing tube spacing is weakening the influenza of the groundwater flow rate to the temperature field The most effective way.(4)Based on the thermal-stream-solid coupling theory,combined with the actual working condition to simulate the freezing process of the contact channel,the temperature field change law obtained by the temperature field change and the flow of thermometrics is compared The results show that the stress field has a small development of the stress field during the frozen process,so the stress field can be ignored when studying the development law of the temperature field during the frozen process.At the same time,based on this model,the surface deformation characteristics excavated after the freeze passage of different buried depths is analyzed,and the grouting provides technical support for future contact channels.