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Harbin Songhua River tunnel at the top of the casing thickness prediction model security


Road safety at the top of the casing thickness prediction model takes into account the individual factors affecting the thickness of the casing the joint security role, that is, equation (14) because of the interconnection between individual impact factors coupling,ralph lauren pas cher, so the individual impact factors thickness of overburden security role of the Which affect the individual safety factors and the thickness of the tunnel between the top casing, and some in front of two or three times the performance of non-linear, but here's where the final prediction model is expressed as a linear or quadratic prescribing nonlinear. 5 Example of a site conditions are in Japan and Harbin river tunnel underwater tunnel site conditions similar instances [3J, inspection of the tunnel from the top of the casing above the safety of the thickness of the validity and reliability of the prediction model. The tunnel site conditions: soil weight degree,, = l8.5kN / m, the cohesion of c = 0.003MPa, internal friction angle = 34., Elastic modulus E = l6.6MPa,abercrombie pas cher, Poisson's ratio = 0.3, water column height h = 2m: the use of shield construction, shield diameter D = 4.8m; design of the casing layer thickness T: 10m. Thickness of overburden above the safe use of predictive models (12) considered the tunnel on the casing layer thickness T = 10.66m, 10m difference between its actual use value of 6.6%. Should be noted that the text [3] did not give examples of the construction of these pressure P, and this institute to be the thickness of the tunnel at the top of the casing safety prediction model calculation (13) is pressure P with the construction of the impact factor, so the count example, using equation (13) calculated the thickness of overburden pressure is bound to ignore the construction of P. However, if the pressure P will be considered top of the tunnel construction safety casing thickness calculation results have a greater impact, so in conjunction with Shanghai Dapu river tunnel shield construction of the actual jacking pressure 78400kNt41,abercrombie pas cher, here added to the above example is true a construction pressure 57.6 kPa) considered the results of 9.87m, the error is 13%. If the combination of the Shanghai trial of the actual construction of shield tunnel jacking pressure 09600kN),mbt chaussures paris, here the above examples plus a virtual construction pressure 85kPa [= 6% × 19600 / (Wu D / 4), D = 4.2m], then type 03) considered the results of 12.9m, the error is 29%: 04 by type) results l2.06m, error of 20.6%. Therefore, the construction of jacking pressure will directly affect the size of the safety of the tunnel at the top of the casing thickness calculations J. Thus, in this paper has the similar conditions and field conditions, this study of the safety of the tunnel at the top of the casing thickness prediction model, the preliminary construction of the tunnel will be designed to provide a theoretical basis. This also proves that this preliminary research ideas and research methods is feasible. 6 Conclusion (1) affect the thickness of the tunnel at the top of the casing of the many safety factors to soil shear strength is most important, the tunnel cavern diameter and soil Poisson's ratio times. In addition to soil friction angle of the body, the tunnel project across the river on Harbin's actual condition, the other major factor affecting the Department of the casing with the term safe use of the relationship between the thickness of a linear function to describe it is feasible to meet the project the accuracy requirements. (2) we can see from Table l, the impact factor based on the individual security and the thickness of the tunnel at the top of the casing fitting relationship between the safety of the thickness of the casing to the top of the results of the calculation, under the same conditions with the finite element analysis results are very match. (3) gives the final thickness of the tunnel at the top of the casing safety prediction model, can fully consider the combined effects of the major impact factor, the correlation coefficient. These formulas reflect the prediction model with high accuracy, and they can withstand the test of engineering study.
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