隧洞掘进机开挖的围岩-支护系统联合承载数值分析

对隧洞掘进机(TBM)开挖过程围岩-支护的联合承载特性进行了数值分析.首先详细分析了在TBM掘进时,围岩和支护的相互作用过程和各种荷载的属性.然后,提出了TBM施工围岩稳定和支护受力的计算方法,主要考虑了施工作用力、开挖荷载和外水压力荷载.提出了确定TBM施工过程中围岩单独承担开挖荷载比例的计算方法.最后结合某大型供水工程,采用上述方法分析了TBM掘进段II—V类围岩稳定和支护受力特性.计算结果既符合一般规律,也提供了定量评估围岩承载能力的方法,能够充分反应不同岩性下围岩-支护系统的联合承载特性,并从数值分析角度论证了衬砌设计的合理性.     

二次支护围岩-支护结构耦合作用黏弹性解析

在地下岩体工程中,无论是软岩还是硬岩,只要岩体受力后的应力水平达到或超过该岩体的流变下限,都将随着时间的增长而发生流变变形.基于此,针对圆形断面巷道,在考虑巷道掘进面空间效应的基础上,根据黏弹性理论,建立巷道围岩与支护结构的二次支护耦合作用模型,并获取解析解.按照该思路,可递推出多次支护情况下围岩与支护结构的耦合作用过程.通过算例分析了初次和二次支护时间对支护结构与围岩以及支护结构与支护结构之间相互作用力的影响.结果显示,支护时间对支护结构与围岩以及支护结构与支护结构之间的相互作用力有显著的影响;当二次支护时间不变时,第1个支护结构与巷道围岩之间的相互作用力随着初次支护时间的增大而减小,第1个支护结构与第2个支护结构之间的相互作用力随着初次支护时间的增大而增大;当初次支护时间不变时,支护结构与围岩以及支护结构与支护结构之间的相互作用力都随着二次支护时间的增大而减小.     

古汉山矿东翼通风疏水大巷锚注支护技术研究

古汉山矿东翼通风疏水大巷先后采用了多种支护方式均未取得成功.为了满足掘进巷道的技术要求,解决巷道的变形,通过对巷道支护与围岩相互作用及目前各类巷道支护形式及支护效果分析研究,决定采用锚注支护方案.其实质是采用注浆锚杆兼作注浆管使用,一方面通过注浆改变围岩的物理力学性能,另一方面又为锚杆提供了可靠的着力基础,提高了锚杆的支护效果.断面内注浆锚杆自下而上先注底脚,再注两帮,最后注拱顶锚杆.掘进巷道500 m,通过现场施工及施工后的监测,巷道能满足设计要求,取得了较好的支护效果.     

深部软岩巷道围岩变形分析与控制

针对某深部软岩巷道支护困难问题,首先对围岩进行力学性能试验,然后利用有限元分析方法,在基于不同埋深软岩巷道围岩变形特征研究的基础上,从巷道开挖和围岩支护两方面对深部高地应力软岩巷道围岩变形与控制进行深入研究.结果表明:随软岩巷道埋深增大,巷道围岩变形呈线性增大趋势;在深部高地应力下掘进巷道时,全断面开挖法围岩变形最大,台阶法次之,CD法最小;支护时采用柔性与刚性联合支护,围岩变形最小.联合支护技术能充分释放软岩巷道围岩变形能,发挥围岩自承能力并与支护体系共同作用,可以有效控制深部软岩巷道围岩变形,从而保证深部软岩巷道围岩的稳定性.     

古汉山矿东翼通风疏水大巷锚注支护技术研究

古汉山矿东翼通风疏水大巷先后采用了多种支护方式均未取得成功．为了满足掘进巷道的技术要求，解决巷道的变形，通过对巷道支护与围岩相互作用及目前各类巷道支护形式及支护效果分析研究，决定采用锚注支护方案．其实质是采用注浆锚杆兼作注浆管使用，一方面通过注浆改变围岩的物理力学性能，另一方面又为锚杆提供了可靠的着力基础，提高了锚杆的支护效果．断面内注浆锚杆自下而上先注底脚，再注两帮，最后注拱顶锚杆、掘进巷道500m，通过现场施工及施工后的监测，巷道能满足设计要求，取得了较好的支护效果．     

岩质隧道开挖最大径向位移的室内模型试验

为研究围岩径向位移与施工工艺间的相互关系,基于围岩开挖扰动时应力响应原理,分析隧道缩尺模型的边界条件及试验方案.通过模型试验,建立岩质隧道的纵向变形规律曲线,获得隧道开挖最大径向位移与施工工艺的变化规律.结果表明:隧道断面径向位移大小与掘进进尺及频次密切相关,此规律可以作为支护方案的参考资料;越接近掘进面,围岩径向位移增大趋势越显著,距掘进面约5倍洞径时,围岩处于自稳状态.为对比分析,基于同样的边界条件,建立了数值模拟研究模型.通过数值计算,验证了缩尺模型试验所得结果的合理性.该研究对支护结构的优化分析设计有一定指导意义.     

深埋软岩隧道不同施工工法力学效应分析

针对穿越软岩地段深埋隧道施工易坍塌的状况,在支护结构类型和参数一致的情况下,采用有限差分程序FLAC3D分别对四种工法(全断面法、台阶法、预留核心土法以及单侧壁导坑法)下隧道的掘进过程进行了三维数值模拟.分析了洞周围岩和支护结构在各种工法下的力学响应规律,并重点探讨了洞周围岩特征点位移、掌子面稳定性以及支护结构受力等效应.根据计算结果对上述四种工法进行了优选,并得出以下结论:从围岩变形及受力方面分析,单侧壁导坑法最优;预留核心土法更适合于深埋软岩隧道的施工;高应力大变形条件下,仰拱处变形应作为围岩稳定判据的关键因素之一;深埋隧道开挖过程中,竖向应力对支护结构影响较强,水平应力对支护结构影响较弱.     

高位巷与工作面回风巷围岩应力变化规律研究

为改变己15-12010工作面回风巷与其上方高位巷掘进相互影响、顶板极其破碎、支护困难的现状,采用数值分析方法对高位巷与回风巷围岩应力变化规律进行了深入细致地研究.结果表明:回风巷与高位巷水平距离为10 m时,两巷围岩应力相互叠加严重,导致回风巷右帮长期处于高应力作用下,致使其右帮及邻近右帮顶板破碎,支护困难;当水平距离达15 m以上后,两巷围岩应力相互影响较小,顶板完整性变好,巷道掘进速度得以大幅提高.     

深埋回采巷道围岩塑性区演化规律研究

基于某矿地应力实测结果,在拟定回采巷道开掘方案及支护参数的前提下,采用Hoekbrown准则、"当量半径"简化、弹塑性平衡理论计算得到巷道掘进支护后围岩塑性区半径公式,假定其他因素不变代入支护强度、侧压系数后得到巷道初掘期间不同部位塑性区与p0、λ耦合关系曲线,为巷道布置及支护强度定量设计提供重要的参数;回采期间假定前两者已定,得到工作面前方14~44 m巷道内围岩塑性区随地质强度因素GSI、支承压力P'变化的演化规律。通过UDEC大变形数值模拟计算获得工作面前方巷道围岩塑性区演化规律和同距离段理论计算结果基本吻合。对掘进、回采期间矿压观测结果表明,基于实测地应力的深埋回采巷道围岩塑性区演化规律研究具有针对性、定量性及实用性,能为巷道布置、支护参数设计及围岩稳定性判定提供可靠的依据。     

人防软岩隧道支护技术的研究与应用

根据软岩大地压、难支护和持续变形破坏的工程特征,提出了软岩隧道关键部位的支护概念,并分析了关键部位的支护原理．工程实践中采用非等强耦合控制技术与注浆强化技术对关键部位实施二次支护,成功控制了围岩的变形,保证了隧道工程的稳定．该控制技术具有简单、安全可靠、掘进速度快、支护费用低等优点,可推广应用．     

巷道围岩变形量与开采深度的关系

本文通过理论分析、相似材料模拟试验、现场实测，总结出巷道围岩失稳的临界深度与围岩性质及支护方式有关，围岩强度越高，失稳的临界深度越大；主动支扩大于被动支护的巷道围岩失稳的临界深度。这些结论对于深部开采巷道布置、支护方式的选择具有重要意义。     

深部开采软岩巷道耦合支护数值模拟研究

通过对深部开采软岩巷道的变形破坏机理的研究发现，巷道变形破坏主要是由于支护体力学特性与围岩力学特性在强度、刚度以及结构上出现不耦合所造成的；且变形首先从关键部位开始，进而导致整个支护系统的失稳．因此，要保证深部软岩巷道围岩的稳定性．必须实现支护体与围岩的耦合．数值模拟研究表明，当锚杆与围岩在刚度上实现耦合时，能最大限度地发挥锚杆对围岩的加固作用；当锚网与围岩在强度上实现耦合时，将会使围岩的应力场和位移场趋于均匀化；当锚索与围岩在结构上耦合时，可以充分利用深部围岩强度来实现对浅部围岩的支护．实践证明，软岩巷道耦合支护可以有效解决深部开采软岩巷道支护问题。     

Rock burst risk evaluation based on equivalent surrounding rock strength

On-site investigations consistently show that the rock burst inherent to coal seams varies greatly with coal seam thickness. In this study, impact factors related to coal seam thickness and surrounding rock strength were analyzed and a corresponding rock burst risk assessment method was constructed. The model reflects the influence of coal seam thickness on the stress distribution of surrounding rock at the roadway. Based on the roadway excavation range, a stress distribution model of surrounding roadway rock is established and the influence of coal seam thickness on rock burst risk is analyzed accordingly. The proposed rock burst risk assessment method is based on the equivalent surrounding rock strength and coal seam bursting liability. The proposed method was tested in a 3500 mining area to find that it yields rock burst risk assessment results as per coal seam thickness that are in accordance with real-world conditions. The results presented here suggest that coal seam thickness is a crucial factor in effective rock burst risk assessment.     

Stress and deformation analysis on deep surrounding rock at different time stages and its application

Based on the characteristics of the deep circular tunnel, the surrounding rock was divided into three regions: the cracked region, the plastic region and the viscoelastic region. The process of rock stress deformation and change was divided into three stages after the roadway excavation. By using the elastic–plastic mechanics theory, the analytical solutions of the surrounding stress and displacement at different stages and the radii of cracked and plastic regions were formulated. We additionally explained the surrounding rock stress and displacement which appeared in practical project. Simultaneously, based on the problem which emerged from a mine in Xuzhou during the excavating process of rock roadway’s transport, we got the theoretical solutions for the stress and displacement in the process of rock roadway’s excavation and considered that the broken area of rock roadway was largely loosing circle. The results indicate that according to the rheological characteristics of surrounding rock, in the primeval excavation of rock roadway, we should increase the length of anchor bolt and cooperate it with anchor nets cable-U steel supporting frame. In addition, when the deformation rate of the surrounding rock is descending after the 15 days’ excavation, we should use the “three anchor” supporting method (anchor bolt spray, anchor note and anchor rope) and set aside about 20 cm as the reserved deformation layer.     

软岩巷道围岩损伤破坏范围的地震探测研究

针对软岩巷道难支护的主要原因是对巷道工程地质条件和围岩结构认识不清、支护对象不明确的问题,论述 了应用地震技术探测软岩巷道损伤破坏范围的可行性,以显德汪矿主运输大巷为试验研究对象,利用地震技术对巷道进行了全断面探测,实现了软弱结构面的空间定位和围岩结构的精确探测,从而为支护形式和参数的选择提供了直观可靠的地质依据。     

三软综放沿空锚网索支护巷道回采期间围岩变形特征

针对三软综放沿空巷道围岩大变形、难支护的特点,提出采用锚网索支护新技术,通过对试验巷道数值模拟以及表面位移、围岩深部位移和围岩应力的现场监测,分析了试验巷道矿压显现活动规律,掌握了试验巷道在锚网索支护下的围岩变形规律,这为锚网索支护在三软煤层巷道的推广应用和支护参数设计提供了科学依据.     

Rules of distribution in a plastic zone of rocks surrounding a roadway affected by tectonic stress

In order to study the rules of distribution in a plastic zone of rocks, surrounding a roadway, affected by tectonic stress, we first analyzed the mechanics of a roadway affected by tectonic stress and derived a theoretical formula for the plastic zone of rocks surrounding a roadway. We also analyzed the distribution characteristics of the plastic zone under different levels of tectonic stress, vertical pressure, cohesion and friction angle of the surrounding rock. Secondly, we used numerical simulation to analyze the range and shape features of the plastic zone of rocks surrounding the roadway, given different tectonic stress levels. Finally we used a rock drilling detector to carry out field measurements on the broken state of rock surrounding the roadway at the -700 substation and channels in the Xinzhuang mine of the Shenhuo mining area. Given the measured ground stress, we analyzed the relationship between tectonic stress and the distribution of this plastic zone. Our results show that the range of the plastic zone at the top and bottom of the roadway increases with an increase in tectonic stress and this increase is especially obvious at the roadway comer.     

深部软岩巷道合理喷层厚度确定

为分析深部软岩巷道锚喷支护合理喷层厚度,以淮南矿区具有典型特征某深部采区软岩巷道为例,采用FLAC3D软件,建立了合理应变软化数值计算模型,基于数值模拟方法分析不同喷层厚度围岩塑性范围及位移场分布,在此基础上进一步分析不同巷道埋深喷层厚度对围岩松动破碎影响。结果表明:深部巷道喷层对围岩塑性圈范围及松动破碎都有显著控制作用。针对淮南矿区典型深部巷道,合理喷层厚度应为200 mm。     

Numerical simulation study of the failure evolution process and failure mode of surrounding rock in deep soft rock roadways

Based on the safety coefficient method,which assigns rock failure criteria to calculate the rock mass unit,the safety coefficient contour of surrounding rock is plotted to judge the distribution form of the fractured zone in the roadway.This will provide the basis numerical simulation to calculate the surrounding rock fractured zone in a roadway.Using the single factor and multi-factor orthogonal test method,the evolution law of roadway surrounding rock displacements,plastic zone and stress distribution under different conditions is studied.It reveals the roadway surrounding rock burst evolution process,and obtains five kinds of failure modes in deep soft rock roadway.Using the fuzzy mathematics clustering analysis method,the deep soft surrounding rock failure model in Zhujixi mine can be classified and patterns recognized.Compared to the identification results and the results detected by geological radar of surrounding rock loose circle,the reliability of the results of the pattern recognition is verified and lays the foundations for the support design of deep soft rock roadways.     

Numerical research on stability control of roofs of water-rich roadway

In order to study the strength-weakening law of roofs of water-rich roadway, this study used FLAC software, and simulated and analyzed the failure characteristics of the surrounding rock of water-rich roadway under the condition of different cross sections and support parameters, finally obtained the stress distribution of the principle stress of the roadway as well as the displacement variation of its surrounding rock. Results indicate that the roof stability of roadway with semicircular cross section is better than the roadway with inclined rectangular cross section under water-rich condition. Besides, the surrounding rock deformation of roadway under the action of water shows a pronounced increase compared to the roadway without the action of water due to the fact that water will obviously weaken the surrounding rock of roadway, especially its roof. It is very beneficial to control roof stability of water-rich roadway and guarantee the roadway stability during its service life by improving the pretension of bolt and cable as well as decreasing inter-row spacing of the bolt.