| 摘要: |
| [目的]针对某水电站工程排沙洞与施工支洞双洞交叉、交叉段结构复杂、洞室跨度大、且拱顶有软弱夹层、利用常规方法无法对其稳定性进行准确分析的现状,寻求一种更准确的分析方法,以指导工程施工.[方法]利用三维有限元方法对施工过程进行跟踪分析,对比不同开挖方案下交叉段围岩的稳定性,并对施工期支护进行了方案设计.[结果]经过对不同施工方案的三维有限元稳定性分析,确定了在排沙洞开挖到施工支洞时,先以短进尺方式开挖施工支洞,并浇筑0.8 m厚混凝土衬砌,以限制软弱夹层变形,减小塑性区和交叉处拱顶拉应力的施工方案.[结论]三维有限元方法在双洞交叉段,能监控确认支护的效果、施工方法是否妥善等,从而及时调整施工方法和修正技术参数,使施工方法和技术更为合理、经济. |
| 关键词: 地下隧洞 双洞交叉开挖 围岩稳定性 三维有限元 |
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| 基金项目:陕西省水利科技计划项目（2003SK-12） |
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| 3D finite element analysis and design of the intersection part of two tunnels |
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| Abstract: |
| 【Objective】 Due to complex structure of the intesecting pant,carge span of the tunnel and a soft stratum across the top of the intersecting trnnel,the stability of the surrounding rock can't be analysed accurately by the conventional method.It is necessary to find out a more accurate method to guide construction.So the research is presented.【Method】 The 3D FEM which tracks construction process is taken to study the stresses and deformations distribution and the stability of the surrounding rocks affected by different excavating projects.And the support measures were planned.【Result】 A construction project is made certain after accurately analysing the stability of surrounding rock under the condition of different excavating projects by the 3D FEM.The project instructs excavating the adit firstly at the intersection part by the method of short-range,and casting concrete 0.8 m as lining in order to prevent the deformations of the soft stratum and decrease the tension and plastic zone on the top of the intersection part arch.【Conclusion】 The results indicate that the 3D FEM can inspect the effect of support and show whether the construction project is proper or not.This makes the modulating of the project in time and modifying the technical parameters coefficients possible and the construction method and technology reason able and economical. |
| Key words: underground tunnels excavating the intersection part the stability of surrounding rocks 3D FEM |
