考虑支护结构作用的地下管廊真实受力模型

True mechanical model of underground pipe corridor supported by piles

为了研究桩撑支护体系对管廊结构受力的影响,以济南市某地下综合管廊工程为例,通过Plaxis 3D有限元软件对该工程进行全过程模拟,发现桩撑支护结构下地下管廊侧板受力呈三段式分布:先增大后减小再增大,明显小于静止土压力,管廊侧板内力小于传统方法。改变廊顶覆土厚度,根据模拟结果拟合得到管廊侧板受力的分布曲线及其简化曲线,同时证明不同覆土厚度下回填土体土压力均为三段式分布,且各段始末位置与覆土厚度有定量关系。计算结果证实,按简化曲线计算所得管廊侧板内力与模拟值较为吻合,即该简化曲线有较好的适用性。按照简化曲线计算管廊侧板荷载,设计得到的管廊结构更加符合实际,更加经济合理。

In order to study the influence of the pile support system on the real mechanical model of the pipe gallery structure, taking an underground comprehensive pipe gallery project in Jinan as an example, the whole process of the project was simulated by using the Plaxis 3 D finite element software. It was found that the stress on the side plate of the underground pipe gallery under the pile support was distributed in three sections: first increase, then decrease, then increase, and obviously less than the static earth pressure, and the internal force of the side plate of the pipe gallery was less than the traditional square law. According to the simulation results, the stress distribution curve and its simplified curve of the side plate of the pipe gallery were obtained by changing the thickness of the covered soil on the top of the gallery. The calculation results showed that the internal force of the side plate of the pipe gallery calculated by the simplified curve was in good agreement with the simulation value, that was to say, the simplified curve had better applicability. According to the simplified curve to calculate the side load of the pipe gallery, the designed pipe gallery structure was more practical, economic and reasonable.