Surrounding rock deformation regularity of roadway under extremely complicated geological conditions in deep mine and its control

By combining the practices of deep mine mining in Changguang Mine field and using the Universal Distinct Element Code 3.0 (UDEC3.0) numerical computing method, the distribution characteristics of deformation field and stress field as well as the surrounding rock deformation regularity of soft rock roadway are analyzed under extremely complicated geolog-ical conditions, a technical principle of bolting to control the surrounding rock of roadway is put forward. And also using a dynamic control for surrounding rocks designing method, the supporting parameters and implement plan are rationally determined. The experimental tests have obtained a good controlling result of surrounding rock.     

Determination of rational support parameters of bolting and shotcreting with wire mesh in soft roadway

Introduction The maintenance of the soft rock roadway is one of main factors that affect the high-production and high-efficiency of mine. The difficult reasons in main-taining this kind of roadway are the large deformation, unstable deformation and different deformation mechanism from other surrounding rock. Because the rock pressure behavior of soft rock engineering and its corresponding control measures are related with rock deformation, so supporting theories and control meth-ods based on t…     

Study on support mechanism of pre-stressed truss cable and its application

The truss cable support technology was put forward to control the large mining height and composite mudstone strata roadway. This technique makes the steady rock in roadway slantwise top be anchor points, makes the truss cable be steady support structure through special implement, and supplied rock in anchor area with horizontal and vertical pressure which strengthens the surrounding rock＇s anti-strain capability, so it can solve the support problem in roadway with the large cross section and large mining height with mudstone strata. The support mechanism of truss cable about how to make the soft strata stabilize is analyzed by use of the mechanical method. Based on the mechanism and numerical simulation method, the truss cable support project was designed and used to the large mining setting room in eleventh mining area of Bailong Mine successfully.     

Convergent mechanism of roadway driven along with strong roof of special thick stratum and its controlled measures

The trapezoidal cross-section roadway, driven along with its medium and fine grain sandstone roof in special thick stratum, was situated in shale strata. Rock-lining wall was employed in roadway, which its roof is in the free situation. Under the action of virgin stress, the surrounding rock of roadway was in stability. While under the action of fixed abutment pressure arisen from protection pillar of roadway, which its two sides‘s eams were extracted, free strong roof of roadway was in the stability. But its two sides‘ rock-lining walls was fractured, partially broken into pieces, and its floor heave was obvious. The velocity of floor heave is 0.440.8 mm/d. The size of broken zone of surrounding rock of roadway increases doubly. An effective load coefficient of surrounding rock to was quoted illustrate these phenomena. The main reasons of roadway convergence are that, rock property of surrounding rock is inferior, protection pillar affects its stability, and supporting pattern employed is improper. At last, effective measures to control roadway convergence should be bolting and grouting lining, which mainly consolidates surrounding rock of roadway.     

RESEARCH ON REPAIR SUPPORT FOR FLOOR HEAVE IN SOFT ROCK ROADWAY

The run-around of Xiagou subincline bottom is a soft rock roadway, its floor has heaved over 1 m. In this paper, by electronic microscope scanning and X-ray diffraction analysis, the components of the soft rock are determined and the breaking mechanism of roadway is analyzed as well. Through finite element calculation and simulation model test, the reasonable repair support method is put forward.     

Research on the bolt supporting principal of developing entry

Based on the principle of rock-soil mechanics, the bolt supporting technology of mine roadway were researched, it is pointed out that the roadway‘s four comer bolt, the prestressed bolt and the extensible bolt play an important role in keeping road stable; it is also indicated that the walls of roadway safeguarded well is important in keeping road stable, which can make the bolt and surrounding rock load-bearing together; bolt and grounting technology can increase anchorage capacity, which is very applicable for soft rock supporting and developing entry.     

Study on strata control by delay grouting in soft rock roadway

The properties of broken rock before and after grouting reinforcement are studied.Testing results show that grouting can raise the residual strength of broken rock, and the bro-ken rockness by grouting can keep the steady supporting capacity within a relatively large de-formation range. Revealing of the characteristics of stage deformation and damage process comes to the conclusion that the supporting of soft rock roadway should be analyzed in a dy-namic view, and the grouting should be delayed at a proper occasion. Based on the above,the stepwise reinforcement technology characterized by immediate shotcreting, timely bolting and delay grouting is put forward and illustrated with a successful engineering practice.     

ANCHORING EFFECT ANALYSIS OF TENSIONED BOLTS

The paper analyses quantitatively the anchoring effect of tensioned bolts on surrounding rock strength, and defines two concepts: one is the surrounding rock strength increased amount △τ13 and the other is the strength influence factor k. The anchoring effect of tensioned bolts is considered to increase a strength increased amount △τ13 where △τ13 is the product k and tensioned load p, i. e. △τ13= kp, where k is a function of two variables x and y. The distributive properties both △τ13 and k are also discussed in the paper, obtaining some useful results for designing bolting support parameters.     

Deformation mechanism of surrounding rocks and key control technology for a roadway driven along goaf in fully mechanized top－coal caving face

The variation of the stress in the bolted surrounding rocks structure of the roadway driven along goaf in a fully mechanized top-coal caving face with moderate stable conditions are studied by using numerical calculation. The essential deformation characteristics of the surrounding rocks in this kind of roadway are obtained and the key technology of bolting sup-port used under these conditions is put forward.     

Analysis of soft rock mineral components and roadway failure mechanism

The mineral components and microstructure of soft rock sampled from roadway floor inXiagou pit are determined by X-ray diffraction and scanning electron microscope. Ccmbined withthe test of expansion and water softening property of the soft rock, the roadway failure mechanism is analyzed, and the reasonable repair supporting principle of roadway is put forward.     

高应力复合型软岩巷道支护技术研究

以某矿井底车场巷道为例，通过对围岩物化分析、力学参数、地应力测试，现场工程地质调查及巷道破坏特征分析，针对该矿软岩巷道围岩变形量大和流变变形显著这两个特点，提出了一次支护采用强力锚喷网、二次支护采用锚注支护是适合该矿岩体特点的合理支护形式，并在该矿西大巷延拓及井底车场巷道、硐空修复中成功应用，取得了良好的技术经济效果。     

深部巷道锚注支护技术应用

锚注支护既加固了围岩,又给锚杆提供了可靠的着力基础,使围岩强度和承载能力得到显著提高,巷道变形量明显降低,锚注支护可以较好地解决深部软岩巷道的支护问题。锚注支护技术的应用解决了高应力软岩巷道的支护问题。根据四水平中央石门返修巷道锚注支护的支护效果可以看出,锚注支护技术适合矿井深部软岩巷道的支护和治理。     

深部冲击地压巷道锚杆支护作用研究与实践

以义马常村煤矿深部冲击地压巷道为工程背景,介绍了深部冲击地压巷道围岩地质力学参数分布特征,分析了冲击地压巷道围岩变形与破坏特征及主要影响因素,揭示出锚杆支护对冲击地压巷道变形的本质作用是保持围岩完整性,在围岩中形成支护应力场,降低应力集中系数,改善巷道围岩应力分布,充分发挥围岩的抗冲击能力。提出冲击地压巷道支护形式选择原则,介绍了高冲击韧性锚杆支护材料力学性能及锚杆支护参数设计方法。针对常村煤矿21220下巷条件,提出以全长预应力锚固、高强度、高冲击韧性锚杆与锚索支护为主,以金属支架为辅的复合支护方式,并进行了井下工业性试验。矿压监测数据表明,该种支护方式与围岩的整体抗冲击能力强,能够有效控制深部冲击地压巷道变形与破坏。在冲击能量影响下,锚杆、锚索受力特征明显不同于普通巷道,呈波浪状或锯齿状变化趋势。     

高应力软岩巷道全断面锚注支护数值模拟分析

采用RFPA2D数值模拟方法,分析巷道在无支护、锚网索+钢棚支护和全断面锚注支护3种形式下巷道围岩的变形破坏和裂隙演化过程。对RFPA2D数值模拟过程研究分析表明,采用全断面锚注支护时,在较高应力作用下巷道围岩仍能保持较好的完整性,基本无明显破坏现象,对软岩巷道稳定性的维护具有显著意义。     

阳城矿深部复合型软岩大巷破坏机制与支护设计

针对阳城煤矿南翼软岩大巷严重底鼓和断面收缩等非线性流变大变形控制难题,综合采用力学试验、现场测试和理论分析等方法,分析了南翼大巷围岩的地质力学特性和破坏特征;通过建立受二向均布载荷作用下的巷道力学模型,研究揭示了阳城煤矿南翼软岩大巷变形破坏力学机制。结果表明:地应力环境对大巷产生了极为不利的影响;大巷围岩属HJS复合型软岩,节理裂隙发育、松动破坏严重,使得可承载的完整岩层厚度较小是大巷破坏严重的关键因素。基于大巷复杂的破坏机制,提出了以锚注为主体的锚网索喷注联合支护方式,并设计使用了新型的注浆锚索,注浆管+注浆锚索深、浅耦合注浆,取得了良好的现场应用效果,实现了软岩大巷变形的有效控制,为类似巷道工程提供了参考。     

高膨胀松软围岩巷道支护技术

为了解决高膨胀松软围岩巷道顶板变形量大、锚杆脱落失效等问题,利用工程类比分析、数值模拟等方法对高膨胀软岩巷道稳定性影响因素及锚杆支护技术进行了研究。研究结果表明:高膨胀松软岩层强度低,遇水易膨胀软化,是顶板破坏失稳的内因,围岩高集中应力及支护强度不足是外因,可通过优化巷道布置方式、加强支护提高巷道稳定性。研究确定了高膨胀软岩巷道树脂加长锚固锚杆锚索组合支护方案,主要参数为:锚杆间排距800 mm×900 mm,锚杆预紧扭矩不小于400 N·m;锚索间排距1 600 mm×1 800 mm,每排2根,锚索预紧力为200~250kN,并将设计支护方案进行了现场试验,取得了良好的支护效果。     

软岩破碎巷道大刚度二次支护稳定原理

从组成岩体的宏观和微观力学性质角度出发，分析了软岩、破碎巷道实施锚网喷二次支护后仍然破坏的原因和影响因素，应用软岩巷道支护理论，提出了一次锚网喷支护和二次料石碹支护的力学模型，分析了各自的力学特点，得出了锚喷网一次支护和大刚度高强度料石碹二次支护的支护方式，破碎、软岩巷道支护稳定原理为：一次支护让压，围岩体受力达到较低变形速率下的力学平衡，充分发挥围岩承载力，大刚度二次支护，减少巷道岩体偏应力，使巷道围岩切向应力相对降低，径向应力相对升高，促进围岩应力向稳定应力状态转化，优化了软岩巷道支护参数.通过在程村矿的软岩、破碎巷道采用二次支护实践，取得了良好的支护效果.     

复合顶板回采巷道锚网索联合支护技术

基于复合顶板回采巷道围岩活动特点,采用动态设计方法,对复合顶板回采巷道进行了锚网梁索支护设计,并通过对巷道支护效果进行监测,认为:复合顶板回采巷道中采用锚网梁索联合支护是可行的,但是在采动影响剧烈阶段围岩变形大,需要进一步优化支护参数或进行二次支护,为类似条件下的锚网索支护设计提供了一定的参考。     

软岩巷道锚喷网支护及监测

结合裴沟煤矿井下实际情况 ,介绍了锚、喷、网联合支护在软岩巷道的应用 ,并着重介绍了围岩变形的监测以及取得的良好技术经济效果     

深井软岩巷道锚注支护结构承载特性

由于受深部高应力的作用，唐口煤矿埋深达1030 m处于软岩地层中的井底车场硐室和巷道均发生了严重的变形破坏，短期内大部分丧失其安全使用功能.针对此情况，提出了锚喷和锚注支护结构，运用相似材料模型进行了试验研究，得到了巷道在不同支护条件下围岩的变形与稳定规律，揭示了唐口煤矿深井巷道顶底板围岩的变形破坏特征.试验结果表明，锚注联合支护结构能够较好地满足深部高地应力作用要求，为同类巷道的支护提供了有效途径.