Heterogeneous information phase space reconstruction and stability prediction of filling body–surrounding rock combination

Traditional research believes that the filling body can effectively control stress concentration while ignoring the problems of unknown stability and the complex and changeable stress distribution of the filling body–surrounding rock combination under high-stress conditions.Current monitoring data processing methods cannot fully consider the complexity of monitoring objects,the diversity of monitoring methods,and the dynamics of monitoring data.To solve this problem,this paper proposes a phase space reconstruction and stability prediction method to process heterogeneous information of backfill–surrounding rock combinations.The three-dimensional monitoring system of a large-area filling body–surrounding rock combination in Longshou Mine was constructed by using drilling stress,multipoint displacement meter,and inclinometer.Varied information,such as the stress and displacement of the filling body–surrounding rock combination,was continuously obtained.Combined with the average mutual information method and the false nearest neighbor point method,the phase space of the heterogeneous information of the filling body–surrounding rock combination was then constructed.In this paper,the distance between the phase point and its nearest point was used as the index evaluation distance to evaluate the stability of the filling body–surrounding rock combination.The evaluated distances(ED)revealed a high sensitivity to the stability of the filling body–surrounding rock combination.The new method was then applied to calculate the time series of historically ED for 12 measuring points located at Longshou Mine.The moments of mutation in these time series were at least 3 months ahead of the roadway return dates.In the ED prediction experiments,the autoregressive integrated moving average model showed a higher prediction accuracy than the deep learning models(long short-term memory and Transformer).Furthermore,the root-mean-square error distribution of the prediction results peaked at 0.26,thus outperforming the no-prediction method in 70%of the cases.

Surrounding Rock Control Technology of Strong Dynamic Pressure Roadway in Hudi Coal Industry

Aiming at the problems of large deformation and difficult maintenance of deep soft rock roadway under the influence of high ground stress and strong dynamic pressure, taking the surrounding rock control of 1105 lane in Hudi Coal Industry as an example, the deformation characteristics and surrounding rock control measures of deep soft rock roadway are analyzed and discussed by means of geological data analysis, roadway deformation monitoring, rock crack drilling and field test. The results show that the main causes of roadway deformation are high ground stress, synclinal tectonic stress, advance mining stress, roadway penetration and surrounding rock fissure development. Based on the deformation characteristics and mechanism of lane 1105, the supporting countermeasures of “roof synergic support, layered grouting, anchor cable beam support, closed hardening of roadway surface” are proposed, which can provide reference for the control of deep roadway surrounding rock under similar conditions.

Experimental Study on Dynamic Mechanical Properties of Sprayed Concrete-Surrounding Rock Combined Body

To investigate the dynamic response problem of the double medium formed by the adherence of sprayed concrete and surrounding rock in the tunnel,a split Hopkinson pressure bar of 75 mm in diameter was adopted at the ages of 3,7 and 10 d.Experimental results showed that dynamic compressive strength and dynamic increase factors(DIF)of the combined bodies increase with the strain rate.With the growth of strain rate,the critical strain of the combined bodies first increases,then deceases.Furthermore,the combined bodies of 3 d reveal the plastic property and brittle property for 7 d and 10 d when the strain rate is over 80/s.The failure characteristic of the sprayed concrete changes from tearing strain damage to crushing damage as the growth of strain rate,and the failure characteristic of rock presents the tensile failure mode as demonstrated by the scanning electron microscope(SEM).

Combined blasting for protection of gob-side roadway with thick and hard roof

The deformation control of surrounding rock in gobside roadway with thick and hard roof poses a significant challenge to the safety and efficiency of coal mining.To address this issue,a novel approach combining directional and non-directional blasting techniques,known as combined blasting,was proposed.This study focuses on the experimental investigation of the proposed method in the 122108 working face in Caojiatan Coal Mine as the engineering background.The initial phase of the study involves physical model experiments to reveal the underlying mechanisms of combined blasting for protecting gob-side roadway with thick and hard roof.The results demonstrate that this approach effectively accelerates the collapse of thick and hard roofs,enhances the fragmentation and expansion coefficient of gangue,facilitates the filling of the goaf with gangue,and provides support to the overlying strata,thus reducing the subsidence of the overlying strata above the goaf.Additionally,the method involves cutting the main roof into shorter beams to decrease the stress and disrupt stress transmission pathways.Subsequent numerical simulations were conducted to corroborate the findings of the physical model experiments,thus validating the accuracy of the experimental results.Furthermore,field engineering experiments were performed,affirming the efficacy of the combined blasting method in mitigating the deformation of surrounding rock and achieving the desired protection of the gob-side roadway.

破碎围岩巷道变形失稳特征及控制技术

针对破碎围岩巷道变形量大、围岩整体性差和支护困难等问题,以昌兴煤矿1460运输石门为试验地点,通过数值模拟与现场考察,研究原支护技术下巷道围岩变形失稳特征及机制,拟采用联合支护技术并对比分析围岩变形特征。研究表明:由于围岩强度低、支护方式单一、受开采动压影响和围岩中含软弱夹层,造成围岩松散破碎,稳定性差,顶板最大破坏深度达到4.80 m;提出了“锚网喷+U型棚拱形支架+注浆”联合支护技术,采用预应力锚索、高刚度U型钢棚、浅孔注浆及深孔锚注等支护方式强化围岩特性,形成多层复合加固拱承载结构,实现支护结构与围岩的相互耦合作用;数值模拟分析得出,修复后围岩塑性屈服区最大深度由5.56 m减小到1.07 m,降低了80.76%,围岩塑性区大幅度减小,围岩应力总体趋于均匀分布;现场试验表明,修复后顶底板位移量仅113 mm,两帮位移量78 mm,说明该联合支护技术方案可有效控制围岩变形失稳,维持巷道整体稳定。

极近距离煤层下伏回采巷道围岩控制技术研究

针对极近距离煤层下伏巷道支护难度大的问题,采用数值模拟、理论分析、现场实践相结合的研究方法,开展极近距离煤层开采底板下伏巷道围岩稳定性控制技术研究,得出:极近距离煤层开采底板下,将下伏回采巷道相对上覆残留煤柱中线错开12~16 m距离布置,有利于下伏回采巷道支护稳定,并在此基础上提出锚杆+金属网+金属棚架的联合支护方案,应用效果良好,为类似条件下的巷道支护提供了有意义的参考。

软岩硐室锚网(索)喷联合支护工艺研究与应用

软岩条件一直是影响矿山巷道稳定的主要因素,对于软岩条件下施工的井下大型硐室,其支护稳定问题尤为重要。针对烂泥沟金矿井下软岩岩体稳固性差、支护体稳定性差、巷道变形大、返修率高的问题,依据软岩围岩变形特征和支护原理分析,结合烂泥沟金矿井下围岩条件变化特征,进行了锚网索喷联合支护工艺的研究与实践。研究实践发现,烂泥沟金矿软岩围岩暴露后及时地进行喷浆封闭处理,能够有效阻止岩块的位移,随后锚网支护加强岩体荷载承受力,待围岩充分释放变形能后,采取加强支护手段可有效控制围岩变形。监测结果表明,该支护方案取得了良好的支护效果,有效地将两帮及顶板岩移控制在允许范围。

回采巷道过断层长短锚索组合支护优化技术

针对玉华煤矿柴家沟井42226工作面运输顺槽过断层时围岩破碎、支护困难、巷道变形严重等问题,分析了原支护方案存在的问题,提出了长短锚索组合支护方案并优化了支护参数。现场实测结果表明,围岩在20 d后开始趋于稳定,顶板最大下沉量为158 mm,底板底鼓量最大为92 mm,两帮收缩量最大为166 mm,分别为原变形量的21.9%、16.4%和25.5%。顶板和两帮锚索受力在13 d后开始逐步稳定在275~285 kN且有小幅度震荡,承载能力还有较大富余,巷道围岩变形得到了有效控制,能够满足安全生产的需要。

沿空留巷围岩控制技术在2-300采面的应用

干河煤矿2-300工作面开采厚煤层,采用110工法。为控制工作面沿空留巷的围岩变形,设计了“切顶卸压+恒阻锚索”围岩控制方案,配合使用“金属网+钢筋网+可伸缩U型钢”联合挡杆技术隔绝采空区。应用结果表明,留巷巷道回采期间顶底板移近量最大为76mm,巷帮变形量最大为49mm,围岩变形均在可控范围内。

综采工作面大断面切眼围岩稳定控制研究

综采工作面大断面切眼围岩的稳定性是影响综采工作面正常设备安装与回采的关键因素,以小保当一号煤矿112203综采工作面大断面切眼为研究对象,通过理论分析研究了112203综采工作面大断面切眼顶板变形机理及理论支护参数。采用离散元数值模拟软件建立了UDEC Trigon模型,研究了支护强度对二次成巷顶板裂隙演化规律、破坏模式和损伤程度的影响规律。数值模拟结果表明:合理的支护技术能够控制顶板微裂纹的扩展降低宏观裂隙的发育高度。长短锚索联合支护后顶板岩层中存在的岩石桥能够有效的限制宏观裂缝的形成以及它们之间的相互作用,特别是对交界面区域的重点支护能够降低二次成巷顶板裂隙的发育高度,减弱深部大断面切眼顶板岩层的损伤程度。现场试验表明,采用加长锚索以及单体液压支柱的补强支护后,112203综采工作面大断面切眼两帮移近量稳定在350 mm左右,顶底板移近量稳定在550 mm左右,顶板未出现明显离层,最大顶板离层量为2.4 mm。本文的理论分析及数值模拟有助于理解综采工作面大断面切眼顶板破坏模式,同时为其控制技术参数的设计提供了方法。

联合支护技术在巷道矿压较大区域中的应用研究

煤矿开采期间,巷道围岩会受地应力影响会发生失稳现象,为了确保开采环境安全,要采取支护技术进行处理。以巷道支护发展历史与联合支护理论为切入点,阐述了巷道围岩联合支护的作用,最终依据工程实例,对联合支护技术在巷道矿压较大区域的应用进行探讨,目的就是确保开采作业安全、顺利进行。

张家湾煤业21305巷道围岩变形及巷道支护技术研究

软岩巷道大变形控制是煤矿安全生产面临的重大挑战。为了提高巷道稳定性,保障采煤作业安全,以山西省张家湾煤业21305巷道为例,对巷道大变形特征进行了初步探讨,采用了合理的钢管混凝土支护数值计算方法,提出了“锚索+网格+喷射混凝土+钢管混凝土”组合支护的改进方案,评价了改进后组合支护方案对软岩巷道大变形的控制效果。结果表明,斜壁弧拱钢管混凝土支座的斜壁容易发生破坏,改进后的组合支护系统对控制软岩巷道的大变形效果明显。

基于泡沫混凝土和U型钢的煤矿巷道支护体系研究

针对煤矿软岩大变形巷道,提出了由钢网、锚杆、锚索、喷射混凝土、可压缩U型钢、泡沫混凝土阻尼层、裂隙岩缓冲层组成的组合支护体系。运用了数值分析和现场监测的技术手段。数值分析结果表明,泡沫混凝土能吸收围岩的大部分变形,U型钢的收缩率显著降低,U型钢的平均轴力与泡沫混凝土厚度呈二阶方程关系。在工程实践中,当泡沫混凝土厚度超过30 cm时,阻尼效应不再明显。现场监测结果表明,围岩位移及U型钢受力在组合支护体系初始阶段20 d内均呈增大趋势,但增大趋势减弱。

高强锚注支护技术在破碎围岩巷道围岩控制中的应用

山西A煤矿13089工作面运输顺槽掘进过F16断层,断层影响区域产生的破碎围岩导致巷道支护后围岩失稳。采用数值模拟研究支护后围岩应变演化规律,研究结果可知,顶板来压30 d时巷道围岩失稳,顶板来压40 d时上部断层区域垮落形成沿着断层倾角方向空腔。介绍了高强锚注支护技术工艺,对支护后的巷道进行顶板观测,观测结果可知顶板30 d最大位移量60 mm,巷道整体稳定。

地质构造影响区回采巷道围岩控制技术研究

为实现地质构造影响区回采巷道围岩变形的有效控制,以1309运输顺槽在褶曲及F13逆断层综合影响区围岩控制为工程背景,制定了围岩控制技术方案,并进行了工程应用。结合1309运输顺槽现场地质条件,提出采用以锚网索、U型钢棚为主,辅以滞后注浆的围岩控制技术方案。该方案具有锚网索支护强度大、U型钢棚刚度大及护表效果好等优势。现场应用后,1309运输顺槽顶底板、两帮最大位移量分别为191、142 mm,围岩变形量较小,支护体系始终保持稳定,说明了1309运输顺槽采用的围岩控制方案效果显著,可以实现地质构造影响区围岩变形的有效控制,且该研究成果可为其他类似条件巷道围岩的控制提供经验借鉴。

回风巷过断层破碎带围岩控制技术研究

为解决伊田煤业21510回风巷过断层破碎带可能发生的片帮、冒顶和巷道涌水等问题,分析巷道掘进地质条件,采用FLAC3D软件对巷道正常掘进和过断层期间垂直应力分布和塑性区发育进行数值模拟。结果显示,与正常区段相比,过断层掘进期间围岩应力和塑性区发育范围均明显增加,断层活化,掘进破坏影响范围扩大。采用循环注浆和“锚网索梁联合支护”方法进行围岩稳定性综合控制,并对控制效果进行观测,观测期内巷道左、右帮最大位移分别为7.22 mm和10.68 mm,顶底板移近量最大为21.9 mm,围岩控制效果良好。

倾斜底板非对称底鼓灾变机理及灾变模式研究

深部高应力倾斜底板岩层易发生非对称底鼓灾害。采用有限元-离散元耦合数值方法(FDEM)研究倾斜底板非对称底鼓灾变机制、灾变模式,以及岩层倾角对底鼓模式的影响。结果表明:(1)应力驱动型底鼓灾变机制为碎胀性的渐进挤压大变形,环形切向集中应力是造成上述灾变的应力驱动源;(2)当倾角为15°~30°时,非对称底鼓特征明显;当倾角为45°~75°时,非对称特征减弱;当倾角为0或90°时,底板呈对称底鼓特性。

深埋大断面巷硐群围岩控制技术实践

针对深埋大断面巷硐群围岩控制问题,以某矿为工程背景,分别建立单一大断面巷硐、大断面巷硐群数值计算模型,对巷硐群围岩变形、应力分布、塑性区分布、锚杆(索)承载状态进行分析,并对支护效果进行验证。采用间排距800 mm×800 mm,φ22 mm×2 400 mm锚杆对巷硐浅部围岩进行加固,5 200 mm×140 mm×10 mm的T型钢带加φ21.8 mm×8 300 mm锚索将加固的浅部围岩锚固和悬吊在深部围岩中,巷道支护完成后进行全断面喷浆的锚-喷联合支护形式。支护效果表明,该方法可以有效控制巷硐群的围岩变形,保证围岩的稳定性。

锦界煤矿31301运输巷围岩控制技术实践

煤矿工作面开采所导致的运输巷道发生严重变形,对井下运输与生产安全造成威胁。为有效解决由工作面开采所导致的一系列支护安全事故,以锦界煤矿31301运输巷道为研究背景,通过现场实地考察,对运输巷道原支护失效原因进行分析,由此为优化支护方案提供基础,并通过数值模拟与工程实测,对优化后的方案进行了验证。研究结果表明,胀裂、应力集中是巷道原支护失效的内因;数值模拟表明优化后的联合支护方案能够有效的控制巷道的变形;现场实测进一步验证了优化后的联合支护方案的有效性,可为相似工程提供借鉴。

厚煤层大断面巷道围岩控制协同技术研究

针对厚煤层开采过程中围岩稳定性差、支护难度大、巷道变形控制困难等问题,以顾北煤矿14321综采工作面为背景,在综合分析了该工作面地质条件和围岩稳定性的基础上,提出了“树脂锚杆+锚索+菱形网+槽钢梁+M5钢带”联合支护技术思路。采用理论分析和数值模拟方法,研究了不同支护方案对巷道围岩变形的影响,最终确立最佳支护方案。现场监测结果显示:在联合支护后,巷道顶板最大移近量为41mm,两帮最大变形量为50mm,证实了支护方案的有效性及合理性,为以后类似条件下巷道支护提供了技术参考。