4，隧道变形的分析
increasing aspect ratio. These observed trends in variations of the phenomena of stress re-distribution and deformation in rocks surrounding tunnels with tunnel dimensions demonstrate that stress induced instabilities can be effectively regulated by adopting appropriate dimensions relative to rockmass properties and engineering objective.
4，隧道变形的分析
Fig. 79.1 Arched-roof profile tunnel of different height to width(as pect) ratio investigated in this study. Aspect ratio of A 1.2; B 0. 6;C 0.5; D 1.4; E 1.0; F 2.0; and G 0.75 (Scale 1 cm: 3 m)
系统工作原理
激光扫描测距仪发射出激光束遇到隧道内壁反射时重 新被其接收,根据发射与接收时间差的一半汁算出激光 器与階道内壁的距离。当发射的为二维激光时,即可获 得由激光点构成的隧道断面轮廓。基于激光扫描测距 原理的车载式隧道形变动态检測与分析系统进行作业 时,列车处于正常速度行驶状态,单次运行采集的隧道 轮廓数据较少,不能充分反映隧道轮麻状态特征,因此 需要沿同一线路进行周期性检测(《次运行采集构成一 个检測周期),采集海量睹道点云数据,并将周期性检测 数据顧合,充分获取路道壁状态特征,建立出可靠的隧 道轮廓模型,将实际检測数据与未发生形变的搭道轮廓 模型输出数据对比,即可进行形变分析判断。
3，隧道变形的检测
•基于国内外隧道形变检测技术的调研和分析,综合考虑近年来 隧道检测技术和算法理论的主流研究方向,激光检测较为精确 的。二维高速激光扫描测距传感器对隧道形变进行动态检测, 生成隧道洞体净空的三维点云数据,用于隧道轮廓参数的分析 处理与显示。 •隧道形变动态检测技术,属于多传感器技术在隧道基础设施智 能检测领域的综合应用,包括隧道轮廊测量、隧道里程定位和 隧道兰维数据建模H部分研究内容
2，影响隧道变形的基本因素
2）围岩的力学的（强度、变形）、构造（不连续面分布、 各向异性、层状、块状）的特性。 • 围岩的力学特性包括强度特性和变形特性，同时也必须认 识和掌握围岩的构造特性。隧道的工程实践表明：围岩的构 造特性远比力学特性的影响更重要。 •外部因素：人为的因素 1）隧道形状的影响 2）隧道断面尺寸的影响 这两点我稍后以一篇论文的讲解来重点阐述
4，隧道变形的分析
2、 Methodology 1) The tunnel shape for the generic model is an arched-roof rectangular cross-section which consists of an arch (5 m radius) profile roof with 7 m high sidewalls and 10 m span. 2) The probable effect of tunnel dimension on deformation and stress re-distribution mechanism in rocks around the tunnel is studied using the height (H) to width (W) ratio. 3)To implement this, the generic tunnel shape (Fig. 79.1)H/W ratio, 1.2 (12 m/10 m), is to be varied to 0.5, 0.6, 0.75, 1, 1.2, 1.4, and 2.0 in each simulation. To curtail such effect, the arch profile geometry is maintained and adjustments to simulate for size influence are effected by increasing or reducing the arch radius and/or the sidewall
4，隧道变形的分析
Abstract Numerical studies of a generic arched-roof profile tunnel was carried out in order to investigate the influence of geometric size on stress distribution and deformation in rockmass surrounding tunnels which can be optimized in design and construction of underground works. Results show that increasing the aspect ratio of the arched-roof tunnel will cause corresponding increase in the magnitude and size of zone of adverse compressive stress concentration at the tunnel sidewall while the extent of de-stressing zone at the invert /crown decreased. The converse is true for increasing span to height ratio. Similarly, the horizontal displacement of rock mass in the vicinity of the tunnel sidewall shows an increasing trend with increasing aspect ratio of the tunnel. In contrast, the tunnel seems not to experience significant variation in vertical displacement of the floor and roof at
隧道的变形
报告时间 : 2016.10
主要内容
1
隧道变形的种类 影响隧道变形的基本因素 隧道变形的检测
2 3 4
隧道变形的分析
1，隧道变形的种类
• 研究控制技术，首先就要了解和认识隧道开挖后产生的变 形形态及影响变形的各种因素。一般说隧道开挖后的变形，是 各种各样的，也是极为复杂的。 把围岩视为连续介质的场合， 可分3种情况进行研究。 • 1）一般围岩条件下深埋隧道的变形实态； • 2）一般围岩条件下浅埋隧道的变形实态； • 3）特殊围岩条件下隧道的变形实态； • 一般围岩条件下深埋隧道的变形实态 一般围岩条件下隧 道的变形，大体上可以分为以下几种。 • 1）拱顶的沉降变形； • 2）偏压引起的拱脚变形； • 3）偏压引起的侧墙变形。
4，隧道变形的分析
2 、重点探讨 隧道尺寸对围岩应力及变形影响的数值分 析 我以下这篇论文来分析 Numerical Analysis of the Influence of Tunnel Dimensions on Stress and Deformation Around Tunnels in Rocks G.E. Ene, C.T. Davie, and C.O. Okogbue
4，隧道变形的分析
1、 Introduction 1).In all situations, failures are linked to induced stress effects and the response of rockmass in terms of stress re-distribution and deformation (Brady and Brown 1993; Jeager et al. 2008). 2).The key issues in design and construction of the tunnels and caverns in rocks, therefore, is the prediction of the pattern of stress re-distribution and amount of deformation that may result during and after construction. 3).This paper reports a numerical investigation of the effect of tunnel dimensions on stress re-distribution and deformation processes in surrounding rockmass which can enable tunnel dimensions to be optimized in design to modify and regulate the stress-induced failures.
4，隧道变形的分析
1 、谈谈隧道开挖后的变形控制中的几个问题 隧道开挖后，由于初始地应力场的应力释放，其结果 必然引起围岩发生各种形态的变形，如拱顶下沉、两侧 围岩挤入、底部鼓起以及掌子面挤出等，而变形的必然 后果，就是造成围岩的松弛，而当围岩的变形或松弛超 过一定范围时，就会造成崩塌或不稳定。因此，隧道的 设计和施工的目的：一句话来概括：就是千方百计地把 把隧道开挖后的围岩变形或松弛，控制在容许的范围之内 。这就是我们设计施工的基本理念和目的。 为了实现这 个理念和目的，就必须解决2个问题。一个容许变形值问 题，一个是控制技术问题。