南水北调穿越北京地铁13号线清河桥施工优化分析

Optimal construction-design analysis of the Qinghe Bridge of Beijing Metro L-13 in the South-to-North Water-Transfer Project

以南水北调工程盾构施工穿越北京地铁13号线清河桥工程为背景,采用有限元分析方法,针对不同施工加固措施及行车速度条件下所引起的桥面竖向变形、桥墩竖向变形和地表沉降等问题进行了研究。总结了预加固旋喷桩配比参数、注浆配比参数及行车速度等因素对各结构变形的影响程度。结果表明:水灰比为1.00时的旋喷桩,既能控制结构变形,又具有较高的经济和施工效益;水泥浆与水玻璃浆之比为1.0∶1.0时的注浆参数最优;行车速度控制在50 km/h以下时,能较好地控制结构变形的发展。最后通过对施工过程中各结构的变形进行监测,验证了优化结果的合理性。

The aim of this paper is to provide an assistant idea to the optimal construction-design analysis of Qinghe Bridge across Beijing Metro L-13 in the country＇s South-to-North Water-Transfer Project from the point of view of numerical simulation and the field test.Based on the investigation and the original idea of the project of Qinghe Bridge of Beijing metro L-13,the bridge was originally to be set up with 3×25 m continuous beams,with the radius of the water pipelines being 3 m and the angle of metro L-13 to the water pipeline being 83°,thus a three-dimensional solid model demonstrating the numerical relation between the water pipeline and Qinghe Bridge has been established.Later,a numerical simulation model has been worked out with the simulated model for analyzing the bridge＇s likely vertical deformation,its pier＇s and the ground surface＇s likely vertical deformation by using different Chemical Churning Pile parameters,water-cement ratios and slurry parameters of cement-sodium silicate ratios.The velocity coefficient concerning the subway operation speed has also been put into the static analysis.And summarized the effect of different reinforce measures and subway operation speed on the vertical deformation of bridge and other structures.The results of our testing and simulation investigation indicate that the optimal Chemical Churning Pile with water-cement ratio being 1：1,can control the structural deformations and display better economic advantages,whereas the optimized slurry parameters should be made in the cement-sodium silicate ratio of 1：1. Besides,the operation speed should be made in 50 km/h or less so as to be able to resist the development of the likely structure deformation.And,finally,the vertical deformations of bridge and other structures in the construction process are also to be under close scrutiny and the results of optimized construction-reinforcing measures should also be under constant control and checking.The results of our monitoring and engineering testing experiments show indicate that the vertical deformation stress of the bridge and other structures is fit for the results worked out by the three-dimensional solid model,demonstrating that the optimized construction reinforce measures we have proposed are reasonable.Thus,the results of our study on the effect mechanism of the shield construction based on the current fundamental establishments can serve as valuable technology reference to the similar engineering projects under work or in the future.