回采巷道锚杆支护两帮稳定性分析

根据巷道围岩应力变化特点结合锚固体变形破坏的相似材料模拟试验,分析了巷道两帮锚固体的变形破坏特征,指出锚杆支护巷道两帮表面主要发生张性破坏,锚固体内部发生剪切破坏,据此建立起回采巷道锚杆支护两帮稳定的分析模型,提出了两帮稳定的判别准则,即锚固体中锚杆的拉应变必须小于锚杆的允许拉应变,在巷道两帮围岩较松软时,还必须满足巷道周边位移值的要求.     

深井巷道顶板锚固体破坏特征及稳定性分析

结合深井回采巷道围岩锚固体变形破坏特征,分析了深井回采巷道顶板锚固体失稳机理,建立了巷道顶板不同破坏形态的稳定性模型,得出了深井回采巷道锚杆、锚索支护条件下顶板锚固体稳定性力学方程,并结合古汉山矿深井回采巷道锚杆、锚索耦合支护方案开展验证性研究,对现场试验巷道顶板锚固体的稳定性进行了力学求解及数据分析,提出的深井回采巷道锚杆、锚索耦合支护方案支护参数合理,顶板离层量小于25mm、顶底板及两帮位移收敛量小于180mm,均保持在可控范围内,锚杆、锚索耦合支护有利于巷道围岩的稳定.     

深部高应力回采巷道支护技术研究

针对深部开采巷道围岩变形快、变形量大的重大难题,根据兴东矿2121工作面回采过程中巷道围岩的变形特征,通过普氏理论计算出锚杆(索)支护参数,提出了5种不同支护方案,利用FLAC3D数值模拟软件,依次计算出各种方案的顶板下沉量和两帮移近量。结果表明:(1)深部巷道在高应力作用下,巷道围岩变形总量较大,特别是在巷道变形初期,巷道围岩变形速率大,在此条件下采用锚杆索联合支护,可以有效控制围岩的变形和破坏;(2)通过加强两帮的支护,可提高深部巷道围岩整体的承载能力,减少顶板下沉,促进顶板形成稳定结构;(3)增加锚索的预紧力,使锚杆与锚索同步承载,可大大增加支护结构的稳定性,有效控制围岩变形。现场试验表明,锚杆索联合支护可有效提高巷道围岩的承载能力,减少围岩移动和变形,具有良好的支护效果。     

综放全煤平巷锚杆支护模拟试验研究

根据“巷道围岩松动圈支护理论”,以南屯矿３上 煤层综放工作面全煤平巷围岩条件为基础,对不同动压系数、侧压系数、锚杆支护参数条件下,锚杆支护巷道围岩应力分布、围岩变形及巷道破坏规律进行了模拟试验．试验证实,矩形煤巷顶板中存在一个卸压区,巷道两帮和角部区域围岩破坏严重,是支护的重点部位．锚网支护能有效控制采动压力影响下全煤巷道围岩的稳定性．试验得到的结论对于综放全煤巷道锚网支护设计和应用具有指导意义．     

采动巷道岩体变形与锚杆锚固力变化规律

阐述了采动巷道围岩的变形规律,探讨了低阻力端锚和高阻力全锚锚杆在巷道围岩变形损伤过程中锚固力的变化规律,揭示了锚杆支护与围岩的作用机理,为采动巷道锚杆支护的选型设计及扩大使用范围提供了科学依据     

巨厚火成岩侵入区巷道支护研究

为了深入研究巨厚火成岩侵入区巷道围岩破坏规律及控制技术,以双鸭山矿业集团东保卫煤矿为例,监测和探讨该类型巷道矿压显现规律,以巨厚火成岩侵入区地质条件分析为主,对侵入区巷道进行地质力学评估,获得巷道围岩力学和锚固特性。结合工程实际,建立数值模型,优化矿井原有支护参数,在保障巷道围岩稳定的条件下,降低巷道支护和维护成本。矿井采用优化支护方案后,对巷道进行位移监测,结果表明,巷道变形总量较小,能够满足矿井安全生产需要,其中巷道两帮的变形总量大于顶板的,下帮的变形总量大于上帮的,两帮变形滞后于顶板变形,并趋于稳定,新的支护方案达到了预期目标。研究结果可为类似巨厚火成岩侵入区巷道支护提供借鉴和参考。     

软岩巷道锚喷支护破坏分析与对策

软岩巷道锚喷支护破坏原因主要有巷道底板无支护或支护的强度不够,底板流变极易发展,形成了围岩体的流变通道;大部分锚杆支护为低工作阻力值,支护作用没有得到有效发挥;混凝土喷层和围岩体变形不匹配,导致喷层体离层、剪切破坏;钢笆网抵抗破坏和变形的能力弱,降低了网喷层的强度和抗变形能力.采取的支护对策有底板反拱加强支护,避免局部围岩体的整体移动,实现巷道周边岩体的均匀收敛变形;选用长锚杆,更好地控制巷道围岩的变形;初喷混凝土为厚度20mm薄喷层,实现初喷层与巷道围岩体的同步变形;用直径4mm冷拔钢丝编织金属网替代钢笆网,提高网喷层支护体的强度与抗变形能力;二次锚杆支护在复喷混凝土后进行,防止网喷层与围岩体离层现象的发生.     

软岩巷道锚喷支护破坏分析与对策

软岩巷道锚喷支护破坏原因主要有:巷道底板无支护或支护的强度不够,底板流变极易发展,形成了围岩体的流变通道;大部分锚杆支护为低工作阻力值,支护作用没有得到有效发挥;混凝土喷层和围岩体变形不匹配,导致喷层体离层、剪切破坏;钢笆网抵抗破坏和变形的能力弱,降低了网喷层的强度和抗变形能力.采取的支护对策有:底板反拱加强支护,避免局部围岩体的整体移动,实现巷道周边岩体的均匀收敛变形;选用长锚杆,更好地控制巷道围岩的变形;初喷混凝土为厚度20 mm薄喷层,实现初喷层与巷道围岩体的同步变形;用直径4 mm冷拔钢丝编织金属网替代钢笆网,提高网喷层支护体的强度与抗变形能力;二次锚杆支护在复喷混凝土后进行,防止网喷层与围岩体离层现象的发生.     

锚固巷道围岩结构动态响应规律研究

针对冲击矿压显现主要发生在巷道的现状,运用理论分析、数值模拟及工程实践等方法,研究了P波作用下锚固巷道围岩与锚杆动态响应规律.结果表明:巷道迎波侧与侧向位置是重点支护位置;应力波作用是迎波侧围岩变形的主导因素,迎波侧锚杆轴应力先小幅下降而后迅速增大,最后稳定在峰值,而主次承载结构不同的动态响应是侧向位置围岩变形的主导因素,侧向位置锚杆轴应力呈"双峰"特性;结合现场分析了围岩层裂垮落与锚杆冲击拉断两种典型的破坏类型,并从改善支护参数和煤岩体强度弱化两方面提出了防冲建议.     

新型高预应力锚杆支护技术的研究及应用

在总结和研究了巷道围岩与锚杆支护体共同变形破坏规律的基础上,试验研制了具有高预应力的新型钢绞线锚杆.新型锚杆可提供强大的高预应力,能够很好地控制围岩产生的有害变形,实现锚杆与围岩的同步变形,更好地发挥围岩的自承能力.同时预应力钢绞线锚杆安装后不易松动,受外界放炮震动影响小,锚杆材料强度大,用于巷道支护后不仅技术上可行,而且同等支护强度条件下能够降低支护成本,对深部矿井软岩支护具有重要的推广应用价值.     

Experimental Study of Deformation of Surrounding Rock with Infrared Radiation

According to the practical conditions of coal roadway in Changcun Coal Mine of Lu＇an Mining Group, the deformation of rock surrounding roadway was experimentally studied by means of thermal infrared （TIP,） imaging system in the process of confined compressions. It is found that the model surface TIR temperature （TIRT） changes with the increase of load. Furthermore, TIRT changes non-synchronously in different ranges such as the roof, floor, wall, corners and bolted ranges. The TIRT is higher in the location of stress concentration and bolted ranges than that in the location of stress relaxation and broken ranges. The interaction ranges of bolt and rock are determined preliminarily according to the corresponding relationship of TIRT fields and the strain fields of the surrounding rock. The new method of TIR image processing has been proved to be effective for the study of bolt support and observation of roadway stability under mine pressure.     

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.     

Numerical analysis of the effects of rock bolts on stress redistribution around a roadway

Besides opening geometry, in situ stress and material properties, opening support also has significant effects on stress redistribution around a roadway. To investigate these effects of rock bolts on the stress redistribution around a roadway, a series of numerical studies were carried out using the finite difference method. Since the stress changes around a roadway caused by rock bolting is small relative to the in situ stress, they cannot obviously be observed in stress contour plots. To overcome this difficulty, a new result processing methodology was developed using the contouring program Surfer. With this methodology, the effects of rock bolts on stress redistribution can obviously be analyzed. Numerical results show that in the three patterns of rock bolts installed in the roof, in the roof and the two lateral sides, and in all the four sides of the rectangular roadway, the maximum stress magnitude of the increase is 0.931 MPa, 2.46 MPa,and 6.5 MPa, respectively; the bolt number of 5 can form an integrated ground arch; the appropriate length and pre-tensioned force of the rock bolt is 2.0 m and 60 k N, respectively. What is more, the ground arch action under the function of rock bolting is able to be effectively examined. The rock bolts dramatically increase the minor principal stress around a roadway which results in significant increase in material strength. Consequently, the major principal stress that the material can carry will greatly increase.With adequate supports, an integrated ground arch which is critical for the stability of roadway will be formed around the roadway.     

锚固体强度与组合拱承载能力的研究与应用

通过模拟试验证明了锚固力的作用在于提高巷道周边破裂围岩的残余强度,并使锚固体形成组合拱．研究了锚固组合拱承载能力的理论计算问题并应用于工程实践,有效地控制了软岩巷道围岩．     

Non-destructive testing and pre-warning analysis on the quality of bolt support in deep roadways of mining districts

The bolt support quality of coal roadways is one of the important factors for the efficiency and security of coal production. By means of a self-developed technique and equipment of random non-destructive testing, non-destructive detection and pre-warning analysis on the quality of bolt support in deep roadways of mining districts were performed in a number of mining areas. The measured data were obtained in the detection instances of abnormal in-situ stress and support invalidation etc. The corresponding relation between axial bolt load variation and roadway surrounding rock deformation and stability was summarized in different mining service stages. Pre-warning technology of roadway surrounding rock stability is proposed based on the detection of axial bolt load. Meanwhile, pre-warning indicators of axial bolt load in different mining service stages are offered and some successful pre-warning cases are also illustrated.The research results show that the change rules of axial bolt load in different mining service stages are quite similar in different mining areas. The change of axial bolt load is in accord with the adjustment of surrounding rock stress, which can consequently reflect the deformation and stability state of roadway surrounding rock. Through the detection of axial bolt load in different sections of roadways, the status of real-time bolt support quality can be reflected; meanwhile, the rationality of bolt support design can be evaluated which provides reference for bolting parameters optimization.     

A local homogenization approach for simulating the reinforcement effect of the fully grouted bolt in deep underground openings

Fully grouted bolts are a key component of the support system for underground openings. Although considerable effort has been made in the simulation of the reinforcement effect of the fully grouted bolts on the rock masses surrounding underground openings, most of the work has limited significance since the structural element approach is used. This study proposes a local homogenization approach (L-H approach) that integrates elastoplastic mechanics, composite mechanics, and analytical approaches with numerical simulation to effectively simulate the reinforcement effect of the fully grouted bolt on deep surrounding rock masses. In the L-H approach, the representative volume of bolted rock mass (RVBRM) with a fully grouted bolt is established based on the original mesh model utilized in the rockbolt element approach. The RVBRM is a regular quadrangular prism with a cross-sectional size equal to the bolt spacing and a length equal to the bolt length. The RVBRM is homogenized by the L-H approach from a unidirectional bolt-reinforced composite into a homogeneous transversely isotropic medium whose mechanical properties are described by a new transversely isotropic elastoplastic model. The L-H parameters for the RVBRM are obtained using analytical approaches, composite mechanics, and known parameters of the rock mass and bolt. Using the L-H approach, the reinforcement effect of the fully grouted bolt on the bolted rock specimen and the surrounding rock mass in Jinping II Diversion Tunnel #2 with a depth greater than 2000 m is simulated. The results show that the predictions of the L-H approach are more in agreement with the physical model results of bolted rock specimen and provide a more realistic response of the bolted surrounding rock mass. The L-H approach demonstrates that fully grouted bolts with common bolt spacings and diameters substantially enhance the elastic modulus, shear strength, and tensile strength of the rock mass in the direction of the bolt axis.     

Stability control of surrounding rocks for a coal roadway in a deep tectonic region简

In order to effectively control the deformation and failure of surrounding rocks in a coal roadway in a deep tectonic region, the deformation and failure mechanism and stability control mechanism were studied. With such methods as numerical simulation and field testing, the distribution law of the displacement, stress and plastic zone in the surrounding rocks was analyzed. The deformation and failure mechanisms of coal roadways in deep tectonic areas were revealed: under high tectonic stress, two sides will slide along the roof or floor; while the plastic zone of the two sides will extend along the roof or floor, leading to more serious deformation and failure in the corner of two sides and the bolt supporting the corners is readily cut off by the shear force or tension force. Aimed at controlling the large slippage deformation of the two sides, serious deformation and failure in the corners of the two sides and massive bolt breakage, a “controlling and yielding coupling support” control technology is proposed. Firstly, bolts which do not pass through the bedding plane should be used in the corners of the roadway, allowing the two sides to have some degree of sliding to achieve the purpose of “yielding” support, and which avoid breakage of the bolts in the corner. After yielding support, bolts in the corner of the roadway and which pass through the bedding plane should be used to control the deformation and failure of the coal in the corner. “Controlling and yielding coupling support” technology has been successfully applied in engineering practice, and the stability of deep coal roadway has been greatly improved.     

深部巷道围岩控制原理与应用研究

采用理论分析、数值模拟和现场试验的方法，研究深部巷道围岩稳定问题，认为深部巷道围岩控制的基本方法是提高围岩强度、转移围岩高应力以及采用合理的支护技术．提出了深部巷道围岩控制的基本技术和控制过程：1）应力转移降低巷道浅部围岩应力；2）采用高预紧力、大延伸量的高强度锚杆、锚索支护系统，强化锚固区围岩强度，提高巷道围岩自身稳定性；3）加强巷道两帮、底角支护，提高巷道最薄弱部位（两帮、底角）残余强度、提高巷道围岩的整体稳定性；4）应用高水速凝材料注浆加固破碎区，提高破碎围岩的完整性和力学参数．该研究成果已成功应用于工程实践．     

锚杆支护作用范围的数值模拟和红外探测实验研究

以潞安矿区巷道锚杆支护参数为基本条件进行数值模拟和物理模型的红外辐射探测实验．使用有限差分软件FLAC^3D模拟了巷道围岩支护前后的位移和应力变化，使用Surfer对数值模拟结果进行二次处理，将锚杆支护后巷道围岩的应力与无支护时的进行相减处理，获得了锚杆支护的作用区域；同时对巷道围岩的红外热像进行相减去噪及对红外增量进行插值和拟合，得到了锚杆支护作用范围的红外辐射温度场变化特征．红外图像处理和数值模拟结果基本一致，为锚杆支护设计提供间、排距安排的理论依据．     

Deformation mechanism and stability control of roadway along a fault subjected to mining

It is difficult to maintain the roadway around a fault because of the fractured surroundings, complex stress environment, and large and intense deformation in the mining process. Based on a tailgate of panel S2205 in Tunliu colliery, in Shanxi province, China, we investigated the evolution of stress and displacement of rocks surrounding the roadway during the drivage and mining period using theoretical analysis, numerical simulation and field trial methods. We analyzed the deformation and failure mechanisms of the tailgate near a fault. The deformation of surrounding rock caused by unloading in the drivage period is large and asymmetric, the roadway convergence increases with activation of the fault and secondary fracture develops in the mining period. Therefore, we proposed a specific control technique of the roadway along a fault as follows: (1) High-strength yielding bolt not only supports the shallow rock to load-bearing structures, but also releases primary deformation energy by use of a pressure release device in order to achieve high resistance to the pressure retained; (2) Grouting of near-fault ribside after initial stabilization of the rock deformation is used to reinforce the broken rock, and to improve the integral load-bearing capacity of the roadway. The research results were successfully applied to a field trial.