深部矿井三维地应力特征及其对巷道稳定性的影响

地应力是影响矿山地下工程围岩稳定性的重要因素之一.为了解狮子山矿区应力状态及分布规律,应用空心包体三轴应变计,采用套孔应力解除法对矿区开展了三维地应力实测.通过实测获得该矿区深部4个中段4个测点的三维应力状态.对实测数据系统分析,获得了矿区地应力场的分布特征,验证了狮子山矿区地应力场以水平构造应力为主导,最大水平主应力的走向为NNW-SSE向,最大、最小及中间主应力随深度基本呈线性增长关系.基于深部三维地应力实测结果和工程地质条件,采用FLAC3D软件分析了巷道轴向与最大主应力方向不同情况下巷道围岩的破坏情况.研究成果为狮子山矿区深部开拓工程和采场的合理布置提供了可靠的依据,对矿山后续安全高效生产具有重要的指导意义.     

平顶山煤业(集团)公司一矿地应力测量及分析

介绍了KX-81型空心包体应变计的测量原理、测量方法,并利用其对平顶山煤业(集团)公司一矿地应力进行了测量,根据实测的结果,分析了矿区地应力场分布特征及其与地质构造的关系.这些分布特征对矿井深部的巷道支护以及对研究煤与瓦斯突出有着重要的指导意义.     

平顶山煤业(集团)公司一矿地应力测量及分析

介绍了KX - 81型空心包体应变计的测量原理、测量方法 ,并利用其对平顶山煤业(集团 )公司一矿地应力进行了测量 ,根据实测的结果 ,分析了矿区地应力场分布特征及其与地质构造的关系 .这些分布特征对矿井深部的巷道支护以及对研究煤与瓦斯突出有着重要的指导意义     

弱胶结软岩巷道围岩位移反演地应力研究

为克服弱胶结软岩钻孔塌陷、遇水软化及崩解给常规地应力测试带来的困难,提出了弱胶结软岩矿区巷道围岩位移反演地应力分析方法.通过在圆形巷道位移解中引入几何修正系数,运用阻尼最小二乘法求得了直墙半圆拱巷道顶板、两帮、底板的修正位移解,基于伊犁四矿软岩巷道围岩位移测试数据,反演得到了该矿区的地应力分布,并结合数值分析进行了地应力正演验证.结果表明:巷道位移修正解、数值模拟值和现场监测值吻合度较高;该矿区地应力场以自重应力为主,最大水平应力是垂直应力的0.7~0.8倍,其方向为NNE~SSW,方位角为10°~20°,对巷道掘进方向和采区布置的影响具有明显的方向性.     

三维地应力场测试及围岩稳定性分析

为解决涡北煤矿-450水平运输大巷破坏严重的问题,采用岩石Kaiser效应法对-450水平进行地应力测量。结果表明:-450水平最大主应力为15.36 MPa,属中高应力区,水平应力过大不利于巷道维护。在地应力测试基础上,应用UDEC数值模拟对变形量进行了预测。研究表明,锚杆支护完全能够满足围岩稳定的要求,可为巷道开挖提供合理的支护方案,为矿区巷道围岩控制提供借鉴和指导。     

地应力场的回归分析与工程应用实例

分析地应力场产生的原因及影响因素，阐述地应力场的回归分析方法，以地应力测点实测资料为基础，建立三维地质模型和数值计算模型，对安徽响水涧抽水蓄能电站厂址区域地应力场进行多元线性回归反演分析。对比实测应力与反演所得应力，两者数值上的差值最大为1.28 MPa,总体误差较小。说明采用应力回归计算求得的初始地应力场能够较真实地反映工程实际情况，可为设计、施工提供有效参考。     

反演理论在隧道及地下工程施工中的应用

依据施工现场实测的应力、应变、位移等信息,反演确定地层的初始地应力及地层特性参数,据此对隧道及地下结构进行设计计算或校核检验,为确定围岩的支护形式、合理的支护时间和合理的结构设计提供便利与依据.     

某水电站地下厂房区地应力场反演

初始地应力是分析工程中围岩稳定性与支护结构的重要参数之一.本文根据某水电站地下厂房区的地应力实测资料,考虑岩体的自重和地质历史构造运动对地应力场的影响,采用多元回归分析法对厂区地应力场进行多元线性回归分析.得出厂区初始地应力函数与应力分布变化规律.反演得到的地应力回归值与实测值在数值大小和应力方向上基本吻合,表明反演获得的地下厂区初始地应力场合理可靠,为地下厂房区的开挖及长期稳定性分析提供重要计算依据.     

双江口水电站初始地应力场反演回归分析

初始地应力是岩土工程设计与施工所要考虑的重要因素之一.根据双江口水电站工程区域实际地质条件以及实测地应力资料,建立了能够反映研究区地貌、岩体结构的地质模型.采用快速拉格朗日计算程序FLAC3D对建立的三维地质概化模型进行计算,在实测点地应力值与计算得到的应力值之间建立多元回归模型,通过多元回归分析,求出最优回归系数.通过实测点的计算应力值与现场实测值的比较,两者在量值上相当且方向上接近,表明经过回归得到的地应力场是合理的,为双江口水电站地下厂房的开挖模拟及长期稳定性分析提供了合理的三维初始地应力场.     

双江口水电站初始地应力场反演回归分析

初始地应力是岩土工程设计与施工所要考虑的重要因素之一.根据双江口水电站工程区域实际地质条件以及实测地应力资料,建立了能够反映研究区地貌、岩体结构的地质模型.采用快速拉格朗日计算程序FLAC3D对建立的三维地质概化模型进行计算,在实测点地应力值与计算得到的应力值之间建立多元回归模型,通过多元回归分析,求出最优回归系数.通过实测点的计算应力值与现场实测值的比较,两者在量值上相当且方向上接近,表明经过回归得到的地应力场是合理的,为双江口水电站地下厂房的开挖模拟及长期稳定性分析提供了合理的三维初始地应力场.     

悬索桥重力式混凝土锚碇稳定性验算与数值分析

锚碇是支承主缆、保证桥梁主体结构受力稳定的重要部位,为保证桥梁安全,锚碇应具有足够的稳定性和力学特性。签于锚碇在悬索桥中的重要性,以重庆长寿长江二桥北锚碇基础为例,通过验算其稳定性以及利用Abaqus3 D进行数值模拟,分析锚碇各施工阶段下的应力状态。结果表明锚碇基础稳定性和压应力满足要求,局部地方出现应力集中和拉应力,应对其进行设计优化处理。锚碇基础的验算和分析结果为重力式混凝土锚碇的合理设计和施工提供有益的参考依据。     

Effects of in-situ stress on the stability of a roadway excavated through a coal seam

Roadways excavated through a coal seam can exert an adverse effect on roadway stability. To investigate the effects of in-situ stress on roadway stability, numerical models were built and high horizontal stresses at varying orientations were applied. The results indicate that stress concentrations, roadway deformation and failure increase in magnitude and extent as the excavation angle with respect to the maximum horizontal stress increases. In addition, the stress adjacent to the coal-rock interface sharply varies in space and evolves with time; coal is much more vulnerable to deformation and failure than rock.The results provide insights into the layout of roadways excavated through a coal seam. Roadways should be designed parallel or at a narrow angle to the maximum horizontal stress. The concentrated stress at the top corner of the face-end should be reduced in advance, and the coal seam should be reinforced immediately after excavation.     

Distribution of ground stress on Puhe Coal Mine

Puhe Coal Mine is a typical Tertiary coal in Shenbei mining area. With an increase in mining depth, tectonic stress field becomes more complex, leading to increased deformation and failure of the soft rock roadway. Stress becomes an important factor of mine safety and stability. This paper analyzes the distribution of the regional tectonic field, and determines the distribution of situ stress measurement through measuring the ground stress field in the main mining area level of Puhe Coal Mine using stress relief method. The acquired in situ stress data at different locations and depths provide a reference for the rational arrangement of the stop and mine roadway supporting design, which are of great significance for the efficient safety production of the mine.     

浅埋偏压隧道开挖数值模拟及稳定性研究

浅埋偏压会对隧道围岩稳定和支护结构产生很大影响,开挖过程中极易发生垮塌。利用FLAC3D 程序对烟海高速公路解家河隧道穿越浅埋偏压洞段采用的施工过程进行仿真分析,得到解家河隧道在采用不同开挖工序时各阶段围岩及支护结构的变形和应力变化情况。结合现场监测断面的量测成果,经过数据整理和计算得到解家河隧道浅埋偏压洞段围岩及支护的受力特征,对隧道围岩稳定性进行分析判断。所得结论为解家河隧道顺利施工提供了可靠依据,可为具有类似地质、地形情况的隧道设计和施工提供技术参考。     

单柱式连续弯箱梁桥研究

本文介绍了北京市东便门立交11号、12号桥的模型实验、现实实测和有限元计算对比分析成果,并针对端部支座反力分布、截面剪应力分布、跨中、中墩截面应力分布、全桥挠度等进行了分析。对单柱式连续弯箱梁桥内力变化进行了初步探讨,为此种桥型的推广使用提供了有益的参考数据。     

Effect of faulting on coal burst——A numerical modelling study

Coal burst occurrence on roadways has always been a major concern in deep underground coal mines,especially under complex geological conditions. To evaluate the effect of faulting on coal burst, the stress concentration in the vicinity a reverse fault was analysed considering the geological history of the fault formation where high horizontal stresses led to the initiation and propagation of the reverse fault.Various in situ stresses and mechanical parameters of the fault, including the ratio of horizontal stress to vertical stress were used to analyse the state of fault. Numerical modelling was conducted using two and three dimensional distinct element models(UDEC and 3 DEC) based on a geotechnical conditions of an Australian underground coal mine. The formation process of reverse fault was simulated to evaluate the stress characteristics in the coal seam and the immediate roof and floor near the fault. The results show that, both the horizontal and vertical stress in footwall were higher than those in hanging wall after the formation of the reverse fault. The stress condition near fault was complicated due to complex geology in the coal measures, and the vertical stress peaked in the footwall at a distance of about 160 m from the fault. When a roadway was excavated, stress concentration occurred at both the roadway face and ribs, which reached as high as 38 MPa in the ribs at a depth of 500 m. This will significantly elevate the risk of dynamic instability of the roadway such as coal burst. The stress concentration zone in the footwall can be considered as a hazardous zone near the reverse fault. This study provides a general reference for analysis of roadway stability affected by faults.     

Measurement and study of the distributing law of in-situ stresses in rock mass at great depth

To solve the technical cruxes of the conventional system in deep rock mass, an automatic testing system for hydraulic fracturing that includes a single tube for hydraulic loop, a pressure-relief valve, central-tubeless packers, and a multichannel real-time data acquisition system was used for in-situ stresses measurement at great depths （over 1000 m） in a coalfield in Juye of Northern China. The values and orientations of horizontal principal stresses were determined by the new system. The virgin stress field and its distributing law were decided by the linear regression from the logged 37 points in seven boreholes. Besides, the typical boreholes arranged in both the adjacent zone and far away zone of the faults were analyzed, respectively. The results show that a stress concentration phenomenon and a deflection in the orientation of the maximal horizontal stress exist in the adjacent zone of the faults, which further provides theoretical basis for design and optimization of mining.     

一种盐岩层蠕变参数的现场评价方法

盐岩层蠕变参数选值的合理性直接影响井壁应力和稳定性分析结果,然而,地面岩心试验常与现场实际情况不符,影响所得的结果的正确性,在假设盐岩层服从粘弹性模型以及7初始地应力和泊松比均为与时间无关的常数的基础上,依据现场量测信息,建立了反演确定盐岩层弹性常数以及粘性常数的反演分析法,研究表明,用现代岩土工程反演理论确定盐岩层的蠕变参数,比做地面岩心试验更符合实际,而且成本低,更加可靠。     

双筒缠绕式提升机卷筒应力分析研究

分析了双筒缠绕式提升机卷筒的受力情况,并对自由筒壳区的强度、支轮强度以及筒壳稳定性计算作了详细介绍,对今后有针对性地设计合理的卷筒结构,减轻卷筒质量,节省材料有着重要的意义,完善了卷筒强度的设计方法。     

松软煤层回风平巷高强U钢支护数值模拟研究

依据永煤集团主焦矿软弱底板的典型地质条件,采用FLAC3D数值模拟的方法研究巷道U29高强度型钢支护下围岩的稳定性,通过与锚喷支护作对照研究,分析得出其应力、位移、塑性区等的变化规律．对U29型铜支护方式进行现场工业性试验,随巷道掘进布置测站,定期监测围岩变形情况及支架的受力状态．结果表明,U29型高强度型钢支架能有效控制围岩变形破坏,支架结构稳定可靠,为保证煤巷的稳定及选择合理的支护形式提供了理论和现场依据．