| With the city Cross-Rive tunnel engineering planning and construction and in objective circumstances of various types of ground buildings, underground building, pile foundation, bridge foundation and underground pipelines, etc, intricate to concentrated distribution in urban areas, it is need to simultaneously excavate two or more adjacent tunnels, or to build a new tunnel in parallel in adjacent exist tunnel because of the building, construction techniques or geological conditions restrictions. If two tunnel net spacing is too small, it will be enormous affect of new tunnel construction on exist tunnel. Therefore, it is necessary to study the affect of new parallel tunnel on exist tunnel. This will provide parallel tunnel design and construction, ensuring the safety of engineering and enhancing the economy and establishing related regulations and standards with good technical support and theoretical basis.Combined with cross-river tunnel of large diameter and great shallow-buried characteristics in Shanghai saturated soft soil layer, the theory and numerical analysis method was used to study cavern deformation characteristics and soil displacement surrounding hole generated due to double holes tunnel excavation and to study the affect of dynamic construction process on exist tunnel. Main research results and conclusions are gat as follows:1, First, interaction theory of the affect of new tunnel construction on cross-river tunnel was established and analytical solution of the influence of new shallow shield tunnel construction on existing tunnel's deformation was deduced using mathematics and mechanics method. Second, using MATLAB mathematical tools, a calculation program was compiled, and then it was obtained for tunnel deformation and surface settlement regularity of the influence of the new shield tunnel on exist tunnel. At last, the limits tunnel deformation was gated by inverse calculation on tunnel lining crack width. Through the comparison of tunnel deformation and limit deformation, close tunnel influence sphere was divided based on theoretical analysis method. 2, It was Established for exist tunnel structure, new shield tunnel and surrounding soils interaction model. Finite difference numerical method was used to study the change of soil stress field and displacement field which was caused by shield tunnel construction and different engineering conditions.3, Combined with Shanghai Renmin road cross-river tunnel engineering and considering the influence of different stages in dynamic construction process, it was analyzed for site monitoring results of existing tunnel's internal force and deformation in new tunnel construction. And then it was contrast analyzed for field measured results,numerical method and theoretical analytic results. The result verified that the theoretical analytic analysis and numerical method is reasonable.4, For three factors: exist tunnels, intermediate soil and new tunnel, it was analyzed of the construction control technology and measures in different influence area. |
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