基于Pasternak弹性地基梁的穿河顶管管幕力学模型及管径优化  

Mechanical model and pipe diameter optimization of a pipe jacking roof in river crossings according to the Pasternak elastic foundation beam

作　　者：牛野[1] NIU Ye(China Railway Siyuan Survey&Design Group Co.,Ltd.,Wuhan 430063,China)

机构地区：[1]中铁第四勘察设计院集团有限公司,武汉430063

出　　处：《地质科技通报》2025年第2期322-329,共8页Bulletin of Geological Science and Technology

基　　金：中铁第四勘察设计院科技研究开发计划“水下复合地层(局部超浅埋)长距离管幕支护技术研究”。

摘　　要：支护管的受力特性分析是顶管管幕结构设计的基础,其保证了隧道开挖的安全。为了分析隧道开挖过程中顶管管幕力学特性,基于Pasternak模型构建管幕底部支护管力学解析模型,充分利用位移、转角、弯矩和剪力连续性条件,推导出支护管位移及内力方程,且计算结果更接近于工程实测应变,证明模型具有适用性。同时以秦淮新河段顶管管幕为例,通过分析支护管最大应变变化规律优选出合理的管幕直径。研究表明:初期管径对管幕底部支护管支护性能影响较大,后期随管径增大影响逐渐减小至平稳;开挖步长和管间间距对支护管支护性能呈正相关影响,小管径时对支护管最大应变影响更明显;管间距对支护管纵向应变影响较小,管幕卸载杠杆作用可有效将开挖区卸载值传递至非开挖区,从而保证管幕开挖面稳定性。The analysis of the force characteristics of the support pipe is the basis for the structural design of the pipe jacking roof,which ensures the safety of tunnel excavation.[Objective]In order to analyze the mechanical behavior of the pipe roof during tunnel excavation,[Methods]an analytical model of the support pipe at the bottom of the pipe jacking roof is constructed based on the Pasternak elastic foundation beam theory,making full use of the displacement,rotation,bending moment,and shear continuity conditions to derive the displacement and internal force equations of the support pipe.[Results]The calculation results are in close agreement with the measured strain from the project,proving the applicability of the model.Moreover,by analyzing the maximum strain change law of the support pipe,the reasonable pipe roof diameter was selected,using the pipe jacking roof of the Qinhuai New River section as an example.[Conclusion]The research shows that the initial pipe diameter significantly influences the support performance of the bottom support pipe,with this influence gradually decreasing as the pipe diameter increases.The excavation step length and pipe spacing positively impact the support performance,with a more pronounced effect on the maximum strain of the support pipe when the pipe diameter is small.Pipe spacing has minimal effect on the longitudinal strain of the support pipe.The unloading lever of the pipe jacking roof can effectively transfer the unloading value from the excavation area to the unexcavated area,thus ensuring the stability of the excavation surface of the pipe jacking roof.

关 键 词：穿河隧道 顶管管幕 Pasternak弹性地基梁 受力特性 管径优化 

分 类 号：TU348[建筑科学—结构工程]