不同缩尺下悬索桥隧道锚原位模型承载特性试验研究  

Experimental study on bearing characteristics of in-situ model of tunnel-type anchorage for a suspension bridge under different scales

作　　者：茆大炜 杜少华 左成荣 梅松华 MAO Dawei;DU Shaohua;ZUO Chengrong;MEI Songhua(PowerChina Zhongnan Engineering Co.,Ltd.,Changsha 410014,China;Hunan Provincial Key Laboratory of Hydropower Development Key Technology,Changsha 410014,China;School of Civil Engineering and Architecture,Henan University of Science and Technology,Luoyang 471023,China)

机构地区：[1]中国电建集团中南勘测设计研究院有限公司,湖南长沙410014 [2]水能资源利用关键技术湖南省重点实验室,湖南长沙410014 [3]河南科技大学土木建筑学院,河南洛阳471023

出　　处：《铁道科学与工程学报》2024年第6期2384-2395,共12页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(42202318)。

摘　　要：为探究隧道锚模型“缩尺效应”引起的试验结果差异性,以丽江金沙江大桥悬索桥实桥隧道锚为研究对象,按照相似理论开展不同缩尺原位模型试验,以期获得不同几何相似比对模型受载后变形变位特性、流变特性、潜在破坏模式及超载性能等方面的响应规律。针对变形和应变等效应量,采用多点式位移计、应变计及压力盒综合测试了锚塞体及周围岩体在不同应力水平下的变形规律与破坏特征;针对长期变形、承载特性,借助气液式加载系统加载到0.824 MPa和2.472 MPa,获得2种荷载下锚塞体及周围岩体的蠕变全过程。结果表明:在各级荷载加载下,模型锚塞体流变阶段变形较大,周边围岩节理裂隙在不同荷载水平作用下被逐渐压密,其中1∶12缩尺条件下的围岩裂隙压密主要发生在第1级荷载过程,1∶20缩尺条件下主要发生在第3级荷载作用下。相比于1∶12缩尺模型,1∶20锚塞体模型变形量较为明显,但两者整体变形特征基本一致,反映围岩破碎程度不利于隧道锚变形稳定。1∶12缩尺模型的后锚面及围岩表面变形分布呈马鞍形,而1∶20缩尺下模型对应的变形分布则呈现双峰形,且2种缩尺下锚塞体板上和围岩的变形残余率均较高。研究结果为分析悬索桥隧道锚因缩尺效应造成的承载特性差异性提供参考。To study the influences of the scale effect on testing results,different scale models of the tunnel-type anchorage of the suspension bridge on the Jinsha River at Lijiang City were established.In-situ experimental tests were carried out with these models according to the similarity theory,yielding the response laws on deformation characteristics,rheological characteristics,potential failure modes,and overload performance under various loading conditions.The deformation patterns and failure characteristics of the anchoring concrete-plug and the surrounding rock at different stress levels were obtained by the comprehensive use of the multi-point displacement meters,strain gauges,and pressure cells.By using the gas-liquid loading system,the long-term deformation and bearing characteristics during the entire creep process of the anchor plug and the surrounding rock were obtained at loading pressures of 0.824 MPa and 2.472 MPa.The testing results indicated that the deformation of the anchoring concrete-plug was relatively large during the rheological stage.The compaction of joints and fissures in the surrounding rock was gradually improved with the loads increasing,among which the compaction of rock fissures with the 1∶12 scale model occurred mainly during loading of the first load level and with the 1∶20 scale model occurred mainly at the load of the third level.The overall deformation characteristics were generally consistent for the 1∶12 and 1∶20 scale models,though the deformation of the latter was larger.This indicated that the degree of fragmentation of the surrounding rock was adverse to the stability of tunnel-type anchorage.The distribution of deformation at the rear surface of the anchor and the surrounding rock surface was saddle-shaped with the 1∶12 scale model and was bimodal-shaped with the 1∶20 scale model.For both models,the residual deformation on the plate of the anchoring concrete-plug and surrounding rock was high.This research can be referred to in future studies on bearing characteris

关 键 词：悬索桥 隧道锚 原位模型试验 缩尺效应 承载特性 

分 类 号：TU45[建筑科学—岩土工程]