热带雨林地区隧道大变形段支护结构优化设计研究

Study on the Optimal Design of Support Structures in Large Deformation Sections of Tunnels Located in Tropical Rainforest Areas

热带雨林地区瞬时降雨量大,降雨持续时间长,导致围岩遇水软化,强度和自持能力均不同程度下降。由此造成常规支护结构无法抑制围岩变形,易发生侵限、掉拱、塌方等突发性安全事故,严重危及施工安全。本研究依托马来西亚热带雨林地区某隧道工程,采用数值模拟和现场监测方法对隧道大变形段初支侵限规律进行了研究,并对隧道变形侵限段支护结构进行了优化设计。研究结果表明:(1)热带雨林地区频繁强降雨下渗会降低隧道围岩的稳定性,增大围岩变形量;(2)隧道发生初期支护变形侵限后,继续掘进将导致变形量持续增大,最终造成隧道坍塌;(3)通过数值模拟结果可知,在使用侵限段径向注浆、锚杆加固等支护参数优化方案后,围岩变形得到有效的抑制。结果表明,本研究使用的支护结构优化设计方案取得了良好的效果,可为类似热带雨林软弱围岩隧道支护结构优化设计提供借鉴和指导。

The tropical rainforest areas often experience heavy and prolonged rainfall,causing surrounding rocks to soften upon contact with water,resulting in a decrease in both strength and self-supporting capacity.Consequently,conventional support structures fail to restrain rock deformation,leading to sudden safety incidents,such as encroachment,collapse,and landslides,posing a serious threat to construction safety.This paper relies on a tunnel project in the tropical rainforest area of Malaysia to study the primary support encroachment law of the large deformation section of the tunnel and to optimize the support structure for the deformed section through numerical simulation and field monitoring methods.The research findings indicate the following.①Frequent heavy rainfall and infiltration in tropical rainforest areas can decrease the stability of the rocks surrounding the tunnel and increase rock deformation.②After the primary support deformation encroachment in the tunnel,further excavation will lead to a continuous increase in deformation,ultimately causing tunnel collapse.③Numerical simulation results show that using optimization schemes,such as radial grouting and anchor reinforcement for encroachment section,for the support parameters effectively suppress rock deformation.The study demonstrates that the support structure optimization design scheme used in this paper has achieved good results and can provide reference and guidance for similar optimization designs of the support structures for tunnels with soft surrounding rocks in tropical rainforest areas.