WO2021007959A1 - 一种模拟巷道围岩裂隙演化的离散元方法 - Google Patents

一种模拟巷道围岩裂隙演化的离散元方法 Download PDF

Info

Publication number
WO2021007959A1
WO2021007959A1 PCT/CN2019/109932 CN2019109932W WO2021007959A1 WO 2021007959 A1 WO2021007959 A1 WO 2021007959A1 CN 2019109932 W CN2019109932 W CN 2019109932W WO 2021007959 A1 WO2021007959 A1 WO 2021007959A1
Authority
WO
WIPO (PCT)
Prior art keywords
rock
roadway
cracks
rock mass
model
Prior art date
Application number
PCT/CN2019/109932
Other languages
English (en)
French (fr)
Inventor
王襄禹
柏建彪
夏军武
闫帅
Original Assignee
中国矿业大学
扬州中矿建筑新材料科技有限公司
江苏博厦矿山科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 中国矿业大学, 扬州中矿建筑新材料科技有限公司, 江苏博厦矿山科技有限公司 filed Critical 中国矿业大学
Priority to RU2020133633A priority Critical patent/RU2746748C1/ru
Priority to US17/043,707 priority patent/US11209415B2/en
Priority to AU2019443098A priority patent/AU2019443098B2/en
Publication of WO2021007959A1 publication Critical patent/WO2021007959A1/zh

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/24—Earth materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/25—Design optimisation, verification or simulation using particle-based methods
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0014—Type of force applied
    • G01N2203/0016—Tensile or compressive
    • G01N2203/0017—Tensile
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0014—Type of force applied
    • G01N2203/0016—Tensile or compressive
    • G01N2203/0019—Compressive
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/0202—Control of the test
    • G01N2203/0212—Theories, calculations
    • G01N2203/0218—Calculations based on experimental data
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2111/00—Details relating to CAD techniques
    • G06F2111/10—Numerical modelling
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/06—Power analysis or power optimisation

Definitions

  • the invention belongs to the technical field of coal mining, and specifically relates to a discrete element method for simulating the evolution of the cracks in the surrounding rock of a roadway.
  • Numerical simulation methods have obvious advantages in solving engineering problems, mainly including finite element and discrete element methods.
  • the discrete element numerical model can simulate the failure process of the rock mass and explicitly simulate the crack propagation and evolution law, which is widely used to solve underground geotechnical engineering problems.
  • the UDEC Trigon model is a discontinuous model that is further improved on the basis of Tyson polygons.
  • the model is composed of a block and a joint surface. Under different stress environments, damage occurs along the joint surface between the blocks, which can be obvious Distinguishing the original fissures and newly generated fissures can more realistically simulate the evolution process of fissures in the surrounding rock of the roadway.
  • the purpose of the present invention is to provide a discrete element method for simulating the evolution of the cracks in the surrounding rock of the roadway, which can effectively and truly restore the scene, and the simulation result is more realistic and reliable.
  • a discrete element method for simulating the evolution of the cracks in the surrounding rock of the roadway adopted by the present invention includes the following steps:
  • the obtained roof core and coal bed core were made into standard rock samples for mechanical experiments: test the uniaxial compressive strength, tensile strength and elastic modulus of the rock sample; according to the elasticity of the rock mass The functional relationship between the ratio of the modulus and the elastic modulus of the rock mass sample and the RQD, and the functional relationship between the uniaxial compressive strength of the rock mass and the uniaxial compressive strength of the rock mass Uniaxial compressive strength and elastic modulus; the tensile strength of the rock mass is 0.1 of the compressive strength of the rock mass;
  • the average value of the side lengths of the triangular blocks in the model is determined according to the statistical crack distribution characteristics in step S1; the uniaxial compressive strength of the rock mass calculated in step S2 Strength, tensile strength and elastic modulus are known eigenvalues, using the correction model to inverse to obtain the triangular block parameters and joint plane parameters in the correction model;
  • step S3 the triangular block parameters and joint surface parameters in the correction model are inverted, including the triangular block size, elastic modulus, and the normal stiffness, tangential stiffness, cohesion, and joint surface of the joint.
  • the specific inversion method for internal friction angle and tensile strength is:
  • step S1 the roadway surface displacement measuring station is installed using the cross point method, the explosion-proof camera is used to record the deformation characteristics of the roadway surrounding rock, and the borehole spy is used to monitor the crack distribution characteristics of the roadway roof and the two sides;
  • the method of drilling tracing is used to quantify the distribution of the length of the cracks on the surface of the drilling.
  • RQD is a rock quality index
  • the specific expression is:
  • l is the cumulative length of the core above 10cm (including 10cm), m; L is the total length of the borehole.
  • step S2 the functional relationship between the ratio of the elastic modulus of the rock mass to the elastic modulus of the rock mass and the RQD is expressed as:
  • E m is the elastic modulus of the rock, GPa
  • E r is the modulus of elasticity of rock samples, GPa.
  • step S2 the functional relationship between the uniaxial compressive strength of the rock mass and the uniaxial compressive strength of the rock mass is expressed as:
  • ⁇ cm and ⁇ c are the uniaxial compressive strengths of rock mass and rock block specimens, respectively, in MPa; the value of m is 0.63.
  • the beneficial technical results of the present invention considering the difference between engineering rock mass and rock block samples, according to the functional relationship between the rock quality index RQD and the ratio of elastic modulus of rock mass and rock mass, and the uniaxial resistance of rock mass and rock mass.
  • the functional relationship between the compressive strength is used to calculate the mechanical parameters of the rock mass.
  • the Trigon module in the UDEC is used to establish a correction model, and the numerical calculation model parameters of the rock mass are obtained by inversion, which can truly and reliably simulate the field roadway deformation characteristics.
  • the parameter correction method for the discrete element simulation of roadway deformation proposed by the present invention fills the gap in the current numerical simulation parameter determination, can truly restore the on-site situation, make the simulation result more real and reliable, and provide a guarantee for safe and efficient mining to a certain extent. Have stronger on-site guidance significance.
  • FIG. 1 Columnar diagram of drilling holes in coal seam
  • Figure 2a The distribution characteristics of the cracks of the coal pillar sill
  • Figure 2b The distribution characteristics of the cracks in the solid coal body
  • Figure 3a The probability distribution diagram of the length of the cracks in the coal pillar
  • Figure 5a The full stress-strain curve of the uniaxial compression of the corrected model
  • Figure 5b The stress-strain curve of the Brazil splitting process of the corrected model
  • Figure 8 Fissure distribution in 7m coal pillar obtained by simulation
  • Fig. 9 is a flowchart of a discrete element method for simulating the evolution of cracks in surrounding rock of a roadway according to the present invention.
  • the example is based on the engineering background of driving along the gob with 7m narrow coal pillars in the 15106 return airway of Yangmei Group Sijiazhuang Mine.
  • the average buried depth of the coal seam is 574m, the average thickness is 5.5m, and the joints and fissures are developed.
  • the 15106 return airway has a total length of 1700m.
  • the roadway is tunneled along the roof of the coal seam, and the tunneling section is rectangular width ⁇ height: 4.8m ⁇ 4.0m, and the columnar diagram of the coal seam borehole is shown in Figure 1.
  • the method of the present invention is now used to correct the parameters of the numerical model that simulates the deformation along the roadway.
  • the discrete element method for simulating the evolution of the surrounding rock cracks in the roadway in this example includes the following steps:
  • the coal body close to the pillar sill has been destroyed and has become a broken area with collapsed holes. .
  • the other side of the coal pillar is the goaf, which cannot be observed with a borehole peeping instrument.
  • the damage degree of the coal pillar near the goaf side should be similar to or more serious than the roadway side. Therefore, it can be determined that after the 15106 return air tunnel was excavated, the internal cracks in the coal pillar developed and the entire coal pillar had been destroyed.
  • the coal seam is broken seriously within 1m from the coal bank, and there are a few cracks in the range of 1m-2m. The coal seam is not affected by mining after the depth exceeds 2m, and it is almost intact. No large cracks are found.
  • the cracks with a length less than 0.2m account for 80% of the total, and the large cracks account for 20% of the total.
  • a comparative analysis of Figures 3a and 3b shows that there are no large cracks in the solid coal body that is not affected by mining, and 20% of the large cracks in the coal pillar are not the original cracks in the natural coal body, but the coal pillar is in the process of formation Produced by destruction, these large fissures do not represent natural primary fissures. Therefore, the length of the primary fissures in the coal seam should be less than 0.2m, which provides basic data for establishing the correction model.
  • step 2) Use the core obtained in step 1) to make a standard sample: a cylinder with a diameter of 50mm and a height of 100mm and a small cylinder with a diameter of 50mm and a thickness of 25mm for uniaxial compression test and Brazilian splitting test.
  • a standard sample a cylinder with a diameter of 50mm and a height of 100mm and a small cylinder with a diameter of 50mm and a thickness of 25mm
  • uniaxial compressive strength, tensile strength and elastic modulus Calculate the strength and elastic modulus of the rock mass according to formulas (II) and (III). The tensile strength of the rock mass is taken as 0.1 of the uniaxial compressive strength.
  • Table 1 The test results are shown in Table 1.
  • E m is the elastic modulus of the rock, GPa
  • E r is the modulus of elasticity of rock samples, GPa.
  • ⁇ cm and ⁇ c are the uniaxial compressive strengths of rock mass and rock block specimens, respectively, in MPa; the value of m is 0.63.
  • the Trigon module in UDEC uses the Trigon module in UDEC to establish a small-size calibration model.
  • the model size is a rectangular model with a width of 2m and a height of 4m for uniaxial compression experiments.
  • the calibration model is shown in Figure 4a.
  • a circular model with a diameter of 2m is used in Brazil.
  • Splitting experiment, the correction model is shown in Figure 4b.
  • the average value of the side length of the triangle block in the model is 0.2m, which can represent the size of the original fracture before the coal seam is disturbed, which is beneficial to distinguish between newly generated fractures and original fractures.
  • the blocks in the model are set as elastic properties, which can be deformed but not destroyed.
  • the joint adopts the Mohr-Coulomb residual strength constitutive model, and the rock mass can only break along the joint plane, and the generation, expansion and penetration of micro-cracks gradually form macro-cracks.
  • the density of the block is the same as the true density of the rock mass, measured in the laboratory.
  • the elastic modulus of the block is the same as the calculated rock elastic modulus.
  • the stiffness of the joint plane is determined according to the size of the model block element and the ratio of Ks/Kn. Iterative trial and error method is used to reverse the cohesion, internal friction angle and tensile strength of the joint surface of the model.
  • the simulation results match the calculated rock mass mechanical parameters (uniaxial compressive strength, tensile strength and elastic modulus).
  • the final mechanical parameters used in the model are shown in Table 2.
  • the criterion of residual strength of joints is that the joint cohesion and internal friction angle after failure are reduced to 0, and only a certain residual internal friction angle remains.
  • the UDEC discrete element software is used to establish a numerical model consistent with the mining scale of the on-site working face.
  • the model is 150m long and 58m high.
  • the key research area is divided into triangular blocks by the Trigon module, as shown in Figure 6.
  • the length of the triangle block in the coal pillar area is 0.2m
  • the length of the triangle block in the coal seam area around the roadway is 0.4m
  • the length of the triangle block in the immediate top and bottom areas of the coal seam is 0.5m.
  • the area outside the study area is divided into rectangular blocks with increasing block length, with block lengths of 1.1m, 2m and 7m. This block size division method can effectively simulate the mechanical behavior of coal pillars.
  • the left and right boundaries of the model are fixed in the horizontal direction, the bottom is fixed in the vertical direction, and the equivalent pressure of the weight of the overburden is applied on the top, and the in-situ measured stress field is applied inside the model.
  • the model parameters are assigned according to the corrected parameters in Table 2.
  • the excavation plan is carried out in accordance with the actual mining sequence. First, the 15108 working face is excavated, and the 15106 return air tunnel is excavated after the model calculates the balance.
  • the coal pillar width is 7m.
  • the support method of the roadway is simulated according to the actual support parameters. Taking the deformation characteristics of the surrounding rock of the roadway and the distribution of cracks obtained in step 1) as a known state, the mechanical parameters of the rectangular block in the large model are obtained by inversion.
  • UDEC Trigon model simulation shows that after 15106 return air tunnel is driven, the distribution of fissures in the 7m-wide coal pillar is shown in Figure 8.
  • coal pillars are divided into large cracks and small cracks. It can be seen from the figure that large fissure areas appear on both sides of the coal pillars.
  • Tension fissures are developed in the range of 2m from the side of the roadway and 3m from the side of the goaf, and become large fissure areas. Shearing fissures develop in the range of 3m ⁇ 4m away from the roadway and become small fissure areas.
  • the simulation results are in good agreement with the on-site drilling peek results (Figure 2a).

Abstract

本发明公开了一种模拟巷道围岩裂隙演化的离散元方法，包括现场煤岩层取芯并记录RQD值，观测巷道变形并统计煤层裂隙分布特征；室内测试煤岩试样的力学参数，根据RQD值计算出岩体的强度；利用UDEC-Trigon模块建立数值模型调整参数与岩体强度相匹配校正模型参数；建立工程尺度的数值模型调整参数与现场变形特征匹配，最终模拟巷道围岩裂隙演化。本发明为离散元数值模拟巷道变形提供准确的基础力学参数，可确保模拟结果真实可靠。

Description

一种模拟巷道围岩裂隙演化的离散元方法 技术领域
本发明属于煤矿开采技术领域，具体涉及一种模拟巷道围岩裂隙演化的离散元方法。
背景技术
煤柱的稳定性一直以来都是安全高效开采需要研究的重点。随着采深增加地质条件复杂，沿空掘巷出现大变形、采空区泄漏瓦斯等现象，巷道围岩控制效果差。煤柱宽度留设不合理，对煤柱和围岩破坏机理的认识不清，导致不能提出长久有效的控制措施，严重的影响煤炭资源安全高效开采。
数值模拟方法在解决工程问题方面具有明显的优势，主要包括有限元和离散元两种方法。离散元数值模型能够模拟岩体的破坏过程并且显式的模拟裂隙扩展演化规律，广泛应用于解决地下岩土工程问题。UDEC Trigon模型是在泰森多边形的基础上进一步改进的非连续模型，模型由块体和节理面两部分组成，在不同的应力环境下沿着块体之间的节理面发生破坏，能够明显的区别原生裂隙和新产生的裂隙，可以更加真实的模拟巷道围岩的裂隙演化过程。
现有的数值模拟方法和技术在模拟巷道变形时存在：模型中岩体力学参数的选取是直接将实验室测得的力学参数应用到数值模型中；而由于实验室采用的试样通常较小，试样是由原岩经过开采、切割后形成，该过程中，内部应力及结构发生变化，从而与真实的大尺度岩体相比，存在较大差异；现有的数值模拟方法和技术忽略了大尺度的工程岩体与小尺度岩块之间的差异性，最终得到的结果与现场实际有较大的偏差，缺乏可信度，并不能指导现场施工。
发明内容
本发明的目的是提供一种模拟巷道围岩裂隙演化的离散元方法，能够有效真实地还原现场，模拟结果更加真实可靠。
为实现上述目的，本发明采用的一种模拟巷道围岩裂隙演化的离散元方法，包括以下 步骤：
S1，在试验巷道内，进行观测巷道变形特征、煤岩样取岩芯；记录巷道围岩变形特征，监测巷道顶板和两帮的裂隙分布特征，在顶板和煤层内取岩芯，记录顶板岩芯及煤层岩芯的RQD值；
S2，将取得的顶板岩芯及煤层岩芯分别制成标准的岩块试样进行力学实验：测试岩块试样的单轴抗压强度、抗拉强度和弹性模量；根据岩体的弹性模量与岩块试样的弹性模量的比值与RQD之间的函数关系，以及岩体的单轴抗压强度和岩块试样单轴抗压强度之间的函数关系，确定岩体的单轴抗压强度和弹性模量；岩体的抗拉强度取岩体的抗压强度的0.1；
S3，应用UDEC中的Trigon模块建立的校正模型，模型中三角形块体的边长的平均值根据步骤S1中统计的裂隙分布特征来确定；以步骤S2中计算得到的岩体的单轴抗压强度、抗拉强度和弹性模量为已知特征值，利用校正模型反演得到校正模型中的三角形块体参数和节理面参数；
S4，利用UDEC建立大尺寸的与现场工作面开采规模一致的数值模型，限定研究区域，在研究区域内利用Trigon模块划分成为三角形块体，三角形块体的边长的平均值以及与三角形块体参数与第三步中校正模型中相同；在研究区域以外的区域划分为长度逐渐增大的矩形块体；以步骤S1中观测得到巷道围岩变形特征和裂隙分布规律为已知状态，反演得到大模型中矩形块体的力学参数。
根据本发明的一些实施例，步骤S3中，反演校正模型中的三角形块体参数和节理面参数，包括三角形块体尺寸、弹性模量和节理面的法向刚度、切向刚度、内聚力、内摩擦角、抗拉强度，具体的反演方法是：
a)分别建立宽高为2m×4m的矩形和直径为2m的圆形校正模型，确保三角形块体的边长的平均值与现场统计的裂隙长度相一致；
b)设置模型中三角形块体的弹性模量与公式(II)计算得到的岩体的弹性模量相同；
c)三角形块体之间节理面的法向刚度K n根据公式(IV)进行推导，切向刚度K s与K n的比值为0.2，泊松比μ根据K s/K n的变化确定；公式(IV)的具体表达式为：
Figure PCTCN2019109932-appb-000001
式中，K和G分别为三角形块体的体积模量和剪切模量，GPa，根据K＝E/3(1-2μ)和G＝E/2(1+μ)来计算，其中μ是块体的泊松比；E是块体的弹性模量，GPa；ΔZ min是相邻单元在垂直方向的最小宽度，m；n取10；
d)利用校正模型进行多次单轴压缩和巴西劈裂实验，得到全程应力应变曲线，采用迭代试错的方法使模拟得到的力学参数与步骤S2中计算得到的岩体的单轴抗压强度、抗拉强度和弹性模量相匹配，最终反演出模型的节理面的内聚力、内摩擦角和抗拉强度。
根据本发明的一些实施例，步骤S1中，利用十字交叉布点法安装巷道表面位移测站，采用防爆相机记录巷道围岩变形特征，应用钻孔窥视仪监测巷道顶板和两帮的裂隙分布特征；采用钻孔描图的方法来量化钻孔表面裂隙长度的分布规律。
根据本发明的一些实施例，步骤S1中，RQD是岩石质量指标，具体表达式为：
Figure PCTCN2019109932-appb-000002
式中，l为10cm以上(含10cm)的岩芯累计长度，m；L为钻孔总长度。
根据本发明的一些实施例，步骤S2中，岩体的弹性模量与岩块弹性模量比值与RQD之间的函数关系，具体表达式为：
E m/E r＝10 0.0186RQD-1.91           (II)
式中，E m为岩体的弹性模量，GPa；E r为岩块试样的弹性模量，GPa。
根据本发明的一些实施例，步骤S2中，岩体的单轴抗压强度和岩块单轴抗压强度之间的函数关系，具体表达式为：
Figure PCTCN2019109932-appb-000003
式中，σ cm和σ c分别为岩体和岩块试样的单轴抗压强度，MPa；m取值为0.63。
本发明的有益技术成果：考虑工程岩体与岩块试样的差异性，根据岩石质量指标RQD与岩体和岩块弹性模量比值之间的函数关系，以及岩体和岩块单轴抗压强度之间的函数关系，来计算岩体的力学参数，采用UDEC中的Trigon模块建立校正模型，反演得到岩体的数值计算模型参数，能够真实可靠的模拟现场巷道变形特征。因此，本发明提出的离散元 模拟巷道变形的参数校正方法填补了目前数值模拟参数确定难的空白，能够真实还原现场情况，使模拟结果更加真实可靠，在一定程度上为安全高效开采提供保障，有更强的现场指导意义。
附图说明
图1煤层的钻孔柱状图；
图2a煤柱帮的裂隙分布特征；
图2b实煤体帮的裂隙分布特征；
图3a煤柱内裂隙长度的概率分布图；
图3b实煤体内裂隙长度的概率分布图；
图4a单轴压缩校正模型；
图4b巴西劈裂校正模型；
图5a校正模型的单轴压缩全程应力应变曲线；
图5b校正模型的巴西劈裂全程应力应变曲线；
图6现场工程尺度的数值模型；
图7数值模拟巷道变形与现场观测对比图；
图8模拟得到的7m煤柱内裂隙分布；
图9本发明一种模拟巷道围岩裂隙演化的离散元方法的流程图。
具体实施方式
下面结合附图及实施例对本发明作进一步详细说明。应当说明，以下实施例仅用于对本发明的说明，并不限定本发明。
实施例以阳煤集团寺家庄矿15106回风巷7m窄煤柱沿空掘巷为工程背景，该煤层平均埋深574m，平均厚度为5.5m，节理裂隙发育，15106回风巷全长1700m，巷道沿煤层顶板掘进，掘进断面为矩形宽×高：4.8m×4.0m，煤层的钻孔柱状图如图1所示。现采用本发明所述的方法对模拟沿巷道变形的数值模型进行参数校正。本实例的模拟巷道围岩裂隙演 化的离散元方法，包括以下几个步骤：
1)在15106回风巷内对完整的顶底板进行取样，记录不同岩性的RQD值。采用中国矿业大学研制生产的YTJ20型钻孔窥视仪对窄煤柱侧和实煤体侧进行探测，在距离底板2m位置处施工水平探测孔，钻孔直径29mm，在煤柱侧打4m深的钻孔，在实煤体侧打20m深的钻孔，观测得到裂隙的分布特征分别如图2a和2b所示。由图2a和2b可知，煤柱侧，在观测的4m范围内都出现大量的环形贯通裂隙和竖向裂隙，靠近煤柱帮部的煤体已经发生破坏，成为破碎区，出现塌孔的现象。煤柱的另一侧为采空区，无法采用钻孔窥视仪进行观测，但是根据钻孔窥视结果推断，煤柱靠近采空区侧的破坏程度应该与巷道侧类似或者更加严重。因此，可以确定15106回风巷在巷道掘进后，煤柱内部裂隙发育，整个煤柱已经发生破坏。实煤体侧，在距离煤帮1m范围内煤层破碎较严重，1m-2m范围内存在少量的裂隙，深度超过2m后煤层未受采动影响，几乎保存完整，没有发现较大的裂隙。
采用钻孔描图的方法，对煤柱内和实煤体内的裂隙长度进行统计分析，结果分别如图3a和图3b所示。由图3a和图3b可知，煤柱内和实煤体内的裂隙长度满足对数正态分布规律。在实煤体内，裂隙长度范围是0.01～0.23m，平均值为0.07m，其中长度小于0.2m的裂隙占总数的99.7％，几乎没有大裂隙(长度大于0.2m)。在煤柱内，裂隙长度范围是0.03～0.59m，平均值为0.13m，其中长度小于0.2m的裂隙占总数的80％，大裂隙占到总数的20％。对比分析图3a和3b可知，在未受采动影响的实煤体内不存在大裂隙，而煤柱中20％的大裂隙并不是天然煤体中的原始裂隙，而是煤柱在形成过程中发生破坏而产生的，这些大裂隙并不能代表天然的原生裂隙。因此，煤层内的原生裂隙长度要小于0.2m，为建立校正模型提供基础数据。
2)利用步骤1)取得的岩芯制作成标准试样：直径50mm、高度100mm的圆柱体和直径为50mm、厚度为25mm的小圆柱体进行单轴压缩试验和巴西劈裂实验，主要测试岩样的单轴抗压强度、抗拉强度和弹性模量。根据公式(II)和(III)来计算岩体的强度和弹性模量。岩体的抗拉强度取单轴抗压强度的0.1。测试结果如表1所示。
表1岩块和计算得到的岩体的力学参数
Figure PCTCN2019109932-appb-000004
Figure PCTCN2019109932-appb-000005
测试结果表明工程岩体与小尺度的岩块试样的力学参数有明显的差异，弹性模量和单轴抗压强度都有不同程度的降低，同时也表明将实验室小石块的力学参数直接带入数值模型中进行计算是不准确的，需要进一步的校正与工程岩体参数相匹配。
其中，岩体的弹性模量与岩块弹性模量比值与RQD之间的函数关系，具体表达式为：
E m/E r＝10 0.0186RQD-1.91          (II)
式中，E m为岩体的弹性模量，GPa；E r为岩块试样的弹性模量，GPa。
岩体的单轴抗压强度和岩块单轴抗压强度之间的函数关系，具体表达式为：
Figure PCTCN2019109932-appb-000006
式中，σ cm和σ c分别为岩体和岩块试样的单轴抗压强度，MPa；m取值为0.63。
3)应用UDEC中的Trigon模块建立小尺寸的校正模型，模型大小为宽2m高4m的矩形模型用于单轴压缩实验，校正模型如图4a所示，直径为2m的圆形模型用于巴西劈裂实验，校正模型如图4b所示。模型中的三角块边长的平均值取值0.2m，能够代表煤层未受扰动前的原生裂隙尺寸，有利于区别新产生的裂隙和原生裂隙。
对4种不同岩性的岩层分别建立模型进行校正。模型内的块体设置为弹性属性，可以发生变形但不会产生破坏。节理采用Mohr-Coulomb残余强度本构模型，岩体只能沿着节理面发生破坏，微观裂隙的产生、扩展、贯通逐渐形成宏观裂隙。
块体的密度与岩体的真实密度相同，通过实验室测得。块体的弹性模量与计算得到的岩体弹性模量相同。节理面的刚度根据模型块体单元的尺寸和Ks/Kn的比例来确定。采用迭代试错的方法来反演出模型节理面的内聚力、内摩擦角和抗拉强度。
利用校正模型进行一系列的单轴压缩和巴西劈裂实验，得到全程应力应变曲线，如图5a和5b所示。
模拟结果与计算得到的岩体力学参数(单轴抗压强度、抗拉强度和弹性模量)相匹配，最终反演出模型中使用的力学参数如表2。节理的残余强度准则认为破坏后的节理内聚力和 内摩擦角都减小为0，只保留一定的残余内摩擦角。
表2校正后的UDEC-Trigon模型力学参数
Figure PCTCN2019109932-appb-000007
力学参数的校正结果如表3所示。由表3可知，校正后的力学参数与目标值之间的误差都小于10％，也证明该参数校正方法的真实可靠性。
表3力学参数校正结果
Figure PCTCN2019109932-appb-000008
4)根据15106工作面的地质条件，采用UDEC离散元软件建立与现场工作面开采规模一致的数值模型，模型长150m，高58m。为提高计算效率，在重点研究的区域利用Trigon模块划分成为三角块体，如图6所示。煤柱区域三角块长度为0.2m，巷道周边煤层区域三角块长度为0.4m，煤层直接顶和直接底区域三角块长度为0.5m。在研究区域以外的区域划分为块体长度不断增大的矩形块体，块体长度1.1m、2m和7m。这种块体尺寸划分方式能够有效地模拟煤柱的力学行为。
模型左右边界在水平方向固定，底部在垂直方向固定，顶部施加上覆岩层重量的等效压力，在模型内部施加原位测量的地应力场。模型参数按照表2中校正的参数进行赋值。开挖计划按照实际的开采顺序进行，先开挖15108工作面，模型计算平衡后再开挖15106回风巷，留设煤柱宽度为7m。巷道的支护方式按照实际的支护参数进行模拟。以步骤1)中观测得到巷道围岩变形特征和裂隙分布规律为已知状态，反演得到大模型中矩形块体的力学参数。
模拟得到的巷道变形与现场观测结果的对比如图7所示。由图可知，巷道在掘进期间就发生严重的变形，顶底板移近量约为592mm，两帮移近量为696mm，与现场距离巷口610m位置处观测的巷道变形(顶底板移近量540mm，两帮移近量645mm，图7b所示)相吻合。图7c～7g对比了数值模拟与现场实测的巷道破坏形式，结果表明现场巷道在采动应力的影响下产生顶板下沉、两帮向巷道空间挤出和底鼓，造成顶板钢带折断和底板铺设的轨道变形，其中煤柱帮变形最大，主要发生在煤柱下半部分，并且挤压运煤皮带。以上现场掘进期间观测到的巷道破坏形式都可以在UDEC Trigon模型中真实的捕捉到，如图7f所示。
UDEC Trigon模型模拟得到15106回风巷掘进后，7m宽的煤柱内裂隙分布情况如图8所示。根据裂隙的分布情况，煤柱被分为大裂隙区和小裂隙区。由图可知，大裂隙区出现在煤柱的两侧，其中距离巷道侧2m范围和距离采空区侧3m范围张拉裂隙发育接近破碎，成为大裂隙区。距离巷道3m～4m范围剪切裂隙发育，成为小裂隙区。模拟结果与现场钻孔窥视结果(图2a)非常吻合。
通过现场尺度的大模型的验证，表明使用校正的参数带入到UDEC Trigon模型中能够真实的模拟现场巷道的变形情况，利用校正后的参数可以进一步预测未来工作面开挖所产生的矿压现象。同时，证明本发明提出方法的可靠性和实用价值。

Claims (6)

  1. 一种模拟巷道围岩裂隙演化的离散元方法，其特征在于，包括以下步骤：
    S1，在试验巷道内，进行观测巷道变形特征、煤岩样取岩芯；记录巷道围岩变形特征，监测巷道顶板和两帮的裂隙分布特征，在顶板和煤层内取岩芯，记录顶板岩芯及煤层岩芯的RQD值；
    S2，将取得的顶板岩芯及煤层岩芯分别制成标准的岩块试样进行力学实验：测试岩块试样的单轴抗压强度、抗拉强度和弹性模量；根据岩体的弹性模量与岩块试样的弹性模量的比值与RQD之间的函数关系，以及岩体的单轴抗压强度和岩块试样单轴抗压强度之间的函数关系，确定岩体的单轴抗压强度和弹性模量；岩体的抗拉强度取岩体的抗压强度的0.1；
    S3，应用UDEC中的Trigon模块建立的校正模型，模型中三角形块体的边长的平均值根据步骤S1中统计的裂隙分布特征来确定；以步骤S2中计算得到的岩体的单轴抗压强度、抗拉强度和弹性模量为已知特征值，利用校正模型反演得到校正模型中的三角形块体参数和节理面参数；
    S4，利用UDEC建立大尺寸的与现场工作面开采规模一致的数值模型，限定研究区域，在研究区域内利用Trigon模块划分成为三角形块体，三角形块体的边长的平均值以及与三角形块体参数与第三步中校正模型中相同；在研究区域以外的区域划分为长度逐渐增大的矩形块体；以步骤S1中观测得到巷道围岩变形特征和裂隙分布规律为已知状态，反演得到大模型中矩形块体的力学参数。
  2. 根据权利要求1所述的一种模拟巷道围岩裂隙演化的离散元方法，其特征在于，步骤S3中，反演校正模型中的三角形块体参数和节理面参数，包括三角形块体尺寸、弹性模量和节理面的法向刚度、切向刚度、内聚力、内摩擦角、抗拉强度，具体的反演方法是：
    a)分别建立宽高为2m×4m的矩形和直径为2m的圆形校正模型，确保三角形块体的边长的平均值与现场统计的裂隙长度相一致；
    b)设置模型中三角形块体的弹性模量与公式(II)计算得到的岩体的弹性模量相同；
    c)三角形块体之间节理面的法向刚度K n根据公式(IV)进行推导，切向刚度K s与K n的比值为0.2，泊松比μ根据K s/K n的变化确定；公式(IV)的具体表达式为：
    Figure PCTCN2019109932-appb-100001
    式中，K和G分别为三角形块体的体积模量和剪切模量，GPa，根据K＝E/3(1-2μ)和G＝E/2(1+μ)来计算，其中μ是块体的泊松比；E是块体的弹性模量，GPa；ΔZ min是相邻单元在垂直方向的最小宽度，m；n取10；
    d)利用校正模型进行多次单轴压缩和巴西劈裂实验，得到全程应力应变曲线，采用迭代试错的方法使模拟得到的力学参数与步骤S2中计算得到的岩体的单轴抗压强度、抗拉强度和弹性模量相匹配，最终反演出模型的节理面的内聚力、内摩擦角和抗拉强度。
  3. 根据权利要求1或2所述的一种模拟巷道围岩裂隙演化的离散元方法，其特征在于，步骤S1中，利用十字交叉布点法安装巷道表面位移测站，采用防爆相机记录巷道围岩变形特征，应用钻孔窥视仪监测巷道顶板和两帮的裂隙分布特征；采用钻孔描图的方法来量化钻孔表面裂隙长度的分布规律。
  4. 根据权利要求3所述的一种模拟巷道围岩裂隙演化的离散元方法，其特征在于，步骤S1中，RQD是岩石质量指标，具体表达式为：
    Figure PCTCN2019109932-appb-100002
    式中，l为10cm以上(含10cm)的岩芯累计长度，m；L为钻孔总长度。
  5. 根据权利要求3所述的一种模拟巷道围岩裂隙演化的离散元方法，其特征在于，步骤S2中，岩体的弹性模量与岩块弹性模量比值与RQD之间的函数关系，具体表达式为：
    E m/E r＝10 0.0186RQD-1.91  (II)
    式中，E m为岩体的弹性模量，GPa；E r为岩块试样的弹性模量，GPa。
  6. 根据权利要求3所述的一种模拟巷道围岩裂隙演化的离散元方法，其特征在于，步骤S2中，岩体的单轴抗压强度和岩块单轴抗压强度之间的函数关系，具体表达式为：
    Figure PCTCN2019109932-appb-100003
    式中，σ cm和σ c分别为岩体和岩块试样的单轴抗压强度，MPa；m取值为0.63。
PCT/CN2019/109932 2019-07-15 2019-10-08 一种模拟巷道围岩裂隙演化的离散元方法 WO2021007959A1 (zh)

Priority Applications (3)

Application Number Priority Date Filing Date Title
RU2020133633A RU2746748C1 (ru) 2019-07-15 2019-10-08 Метод дискретных элементов для моделирования развития разлома в породе, окружающей штрек
US17/043,707 US11209415B2 (en) 2019-07-15 2019-10-08 Discrete element method for modelling a fracture evolution of a roadway surrounding rock
AU2019443098A AU2019443098B2 (en) 2019-07-15 2019-10-08 Discrete element method for modelling fracture evolution of roadway surrounding rock

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201910635883.6 2019-07-15
CN201910635883.6A CN110390152B (zh) 2019-07-15 2019-07-15 一种模拟巷道围岩裂隙演化的离散元方法

Publications (1)

Publication Number Publication Date
WO2021007959A1 true WO2021007959A1 (zh) 2021-01-21

Family

ID=68286508

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/109932 WO2021007959A1 (zh) 2019-07-15 2019-10-08 一种模拟巷道围岩裂隙演化的离散元方法

Country Status (5)

Country Link
US (1) US11209415B2 (zh)
CN (1) CN110390152B (zh)
AU (1) AU2019443098B2 (zh)
RU (1) RU2746748C1 (zh)
WO (1) WO2021007959A1 (zh)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113536442A (zh) * 2021-07-30 2021-10-22 新疆建筑科学研究院（有限责任公司） 一种模拟互层岩体数值模型的仿真方法、系统及处理终端
CN113654477A (zh) * 2021-08-16 2021-11-16 中国矿业大学 一种煤体变形测试装置、测试系统及测试方法
CN114033356A (zh) * 2021-11-24 2022-02-11 中海石油(中国)有限公司 一种煤系地层地应力计算方法及装置
CN114233390A (zh) * 2021-12-20 2022-03-25 中铁二院工程集团有限责任公司 一种适用于软弱围岩的辅助坑道封堵结构及其计算方法
CN114861401A (zh) * 2022-04-08 2022-08-05 武汉大学 一种层状岩体fdem数值模拟输入参数标定方法
CN115600398A (zh) * 2022-10-10 2023-01-13 长安大学（Cn） 一种基于蒙特卡洛模拟的大型洞室岩体参数概率估计方法
CN116385688A (zh) * 2023-06-01 2023-07-04 北京畅图科技有限公司 三维巷道模型快速构建方法、装置、计算机设备及介质
CN117217121A (zh) * 2023-09-14 2023-12-12 国网新源集团有限公司 基于分布式并行topso-ewoa-de算法的岩体力学参数反演方法及系统
CN117251919B (zh) * 2023-10-13 2024-05-17 湖南科技大学 一种沿空留巷顶板侧向破断位置判定方法

Families Citing this family (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110826254A (zh) * 2019-11-27 2020-02-21 神华准格尔能源有限责任公司 露天矿边坡岩体节理分布参数测定方法、存储介质和系统
CN110887749B (zh) * 2019-12-04 2022-04-15 宁波大学 结构面抗剪强度尺寸效应试验试样尺寸确定方法
CN111008486B (zh) * 2019-12-27 2022-11-01 中国矿业大学 一种2d模拟综采面滚筒截割煤壁并统计块煤率的方法
CN111271129A (zh) * 2020-01-31 2020-06-12 天地科技股份有限公司 获取回采巷道围岩变形与裂隙扩展规律的方法
CN111723421A (zh) * 2020-06-04 2020-09-29 中国矿业大学 一种沿空留巷巷旁充填体宽度确定方法
CN111814242B (zh) * 2020-07-16 2023-10-03 新疆工程学院 一种利用物联网数据判定沿空掘巷煤柱宽度的方法及系统
CN112001086B (zh) * 2020-08-26 2024-01-30 湖南科技大学 基于再生顶板分层特性确定漏风裂隙胶结材料组分的方法
CN112906312A (zh) * 2021-01-19 2021-06-04 中国矿业大学(北京) 变节理刚度的裂隙煤岩体流固耦合模拟参数选取方法
CN113240635B (zh) * 2021-05-08 2022-05-03 中南大学 一种裂缝分辨为基准的结构物检测图像质量测试方法
CN113153435B (zh) * 2021-05-17 2022-07-01 中国矿业大学 一种双巷布置系统复采扰动下煤柱加固参数的确定方法
CN113433123A (zh) * 2021-05-24 2021-09-24 中国电建集团贵阳勘测设计研究院有限公司 一种钻孔内地质参数测试方法及智能化装置
CN114419982B (zh) * 2021-12-29 2024-03-15 山东科技大学 软岩地层留煤柱采空区巷道变形破坏的模型试验系统及方法
CN114841003B (zh) * 2022-05-12 2024-04-26 福建省水利水电勘测设计研究院有限公司 围岩最高温度反演计算的方法
CN115203900B (zh) * 2022-06-17 2023-04-18 中国科学院武汉岩土力学研究所 基于离散元的裂隙岩体建模方法
CN115184579B (zh) * 2022-06-20 2023-03-24 北京科技大学 一种空洞塌陷隐患全过程致灾演变试验装置及方法
CN115355008B (zh) * 2022-07-15 2023-09-19 中国矿业大学 一种冲击地压矿井掘进巷道煤岩穿层期间立体式卸压方法
CN115081302B (zh) * 2022-07-15 2023-07-07 中国矿业大学 支护构件与硐室围岩接触及相互作用的模拟方法和系统
CN116502386B (zh) * 2022-09-09 2023-10-31 中国矿业大学 静动荷载作用下巷道锚固围岩灾变演化的模拟方法及系统
CN115828519B (zh) * 2022-11-02 2023-06-23 国网湖北省电力有限公司经济技术研究院 一种输电杆塔基础边坡土石混合体单轴抗压强度计算方法
CN115859714B (zh) * 2022-11-23 2023-06-23 长安大学 一种基于fem-dem联合仿真的岩石爆破全过程模拟方法
CN115906525B (zh) * 2022-12-29 2023-07-25 重庆大学 数值模拟岩层运动过程中力学参数映射关系的确定方法
CN115964901B (zh) * 2023-03-16 2023-05-16 中国科学院地质与地球物理研究所 基于离散单元法的水致岩石强度劣化的模拟方法及系统
CN116467865B (zh) * 2023-04-06 2023-11-24 中国地质大学（北京） 考虑t应力及裂隙参数的岩体压剪断裂模型及其建立方法
CN116861704B (zh) * 2023-09-04 2023-11-14 北京交通大学 一种高地应力软岩隧道大变形等级动态快速预测方法
CN117706068B (zh) * 2024-02-06 2024-04-19 湖南省通盛工程有限公司 一种桥梁基底岩石rqd测定方法、系统和存储介质

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106919770A (zh) * 2017-03-21 2017-07-04 安徽理工大学 一种基于数值模拟的损伤变量确定方法
CN109271738A (zh) * 2018-10-16 2019-01-25 山东科技大学 一种用于获取巷道围岩Weibull分布参数的数值反演方法
CN109492262A (zh) * 2018-10-16 2019-03-19 山东科技大学 一种利用数值模拟分析非均匀分布裂隙巷道稳定性的方法

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013134427A2 (en) * 2012-03-06 2013-09-12 Ion Geophysical Corporation Model predicting fracturing of shale
US9677393B2 (en) * 2013-08-28 2017-06-13 Schlumberger Technology Corporation Method for performing a stimulation operation with proppant placement at a wellsite
CN105093349A (zh) * 2014-05-19 2015-11-25 中国矿业大学 一种实测巷道顶板内部裂隙发展发育规律的方法
US20170131192A1 (en) * 2015-11-06 2017-05-11 Baker Hughes Incorporated Determining the imminent rock failure state for improving multi-stage triaxial compression tests
CN107290506B (zh) * 2017-07-28 2018-04-20 中国石油大学(北京) 一种定量评价储层成岩演化过程中孔隙度时空演变的方法
CN108489809B (zh) * 2018-03-06 2020-06-02 西南石油大学 利用实验手段计算应力作用下粗糙错位裂缝变形量的方法
CN109684785A (zh) * 2019-03-07 2019-04-26 湘潭大学 一种深部高应力巷道围岩动态损伤破坏演化方法及系统
US11098582B1 (en) * 2020-02-17 2021-08-24 Saudi Arabian Oil Company Determination of calibrated minimum horizontal stress magnitude using fracture closure pressure and multiple mechanical earth model realizations

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106919770A (zh) * 2017-03-21 2017-07-04 安徽理工大学 一种基于数值模拟的损伤变量确定方法
CN109271738A (zh) * 2018-10-16 2019-01-25 山东科技大学 一种用于获取巷道围岩Weibull分布参数的数值反演方法
CN109492262A (zh) * 2018-10-16 2019-03-19 山东科技大学 一种利用数值模拟分析非均匀分布裂隙巷道稳定性的方法

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113536442A (zh) * 2021-07-30 2021-10-22 新疆建筑科学研究院（有限责任公司） 一种模拟互层岩体数值模型的仿真方法、系统及处理终端
CN113654477A (zh) * 2021-08-16 2021-11-16 中国矿业大学 一种煤体变形测试装置、测试系统及测试方法
CN114033356A (zh) * 2021-11-24 2022-02-11 中海石油(中国)有限公司 一种煤系地层地应力计算方法及装置
CN114033356B (zh) * 2021-11-24 2023-12-12 中海石油(中国)有限公司 一种煤系地层地应力计算方法及装置
CN114233390B (zh) * 2021-12-20 2023-07-25 中铁二院工程集团有限责任公司 一种适用于软弱围岩的辅助坑道封堵结构及其计算方法
CN114233390A (zh) * 2021-12-20 2022-03-25 中铁二院工程集团有限责任公司 一种适用于软弱围岩的辅助坑道封堵结构及其计算方法
CN114861401A (zh) * 2022-04-08 2022-08-05 武汉大学 一种层状岩体fdem数值模拟输入参数标定方法
CN114861401B (zh) * 2022-04-08 2024-04-05 武汉大学 一种层状岩体fdem数值模拟输入参数标定方法
CN115600398B (zh) * 2022-10-10 2023-06-16 长安大学 一种基于蒙特卡洛模拟的大型洞室岩体参数概率估计方法
CN115600398A (zh) * 2022-10-10 2023-01-13 长安大学（Cn） 一种基于蒙特卡洛模拟的大型洞室岩体参数概率估计方法
CN116385688B (zh) * 2023-06-01 2023-08-15 北京畅图科技有限公司 三维巷道模型快速构建方法、装置、计算机设备及介质
CN116385688A (zh) * 2023-06-01 2023-07-04 北京畅图科技有限公司 三维巷道模型快速构建方法、装置、计算机设备及介质
CN117217121A (zh) * 2023-09-14 2023-12-12 国网新源集团有限公司 基于分布式并行topso-ewoa-de算法的岩体力学参数反演方法及系统
CN117251919B (zh) * 2023-10-13 2024-05-17 湖南科技大学 一种沿空留巷顶板侧向破断位置判定方法

Also Published As

Publication number Publication date
AU2019443098A1 (en) 2021-02-04
CN110390152B (zh) 2021-04-02
US11209415B2 (en) 2021-12-28
AU2019443098B2 (en) 2022-09-22
CN110390152A (zh) 2019-10-29
US20210263003A1 (en) 2021-08-26
RU2746748C1 (ru) 2021-04-20

Similar Documents

Publication Publication Date Title
WO2021007959A1 (zh) 一种模拟巷道围岩裂隙演化的离散元方法
Li et al. Deformation and mechanical characteristics of tunnel lining in tunnel intersection between subway station tunnel and construction tunnel
Sun et al. Experimental and numerical investigation on a novel support system for controlling roadway deformation in underground coal mines
Xia et al. Estimating the geological strength index and disturbance factor in the Hoek–Brown criterion using the acoustic wave velocity in the rock mass
Zhang et al. Squeezing failure behavior of roof‐coal masses in a gob‐side entry driven under unstable overlying strata
Zhang et al. 3D reconstruction method and connectivity rules of fracture networks generated under different mining layouts
Pan et al. Effect of premining on hard roof distress behavior: a case study
CN112035937B (zh) 一种隧道施工围岩变形分析及信息化施工方法
Zhang et al. Experimental investigation of crack propagation behavior and failure characteristics of cement infilled rock
Sun et al. Numerical and theoretical study of bi-planar failure in footwall slopes
Zhang et al. The numerical simulation of permeability rules in protective seam mining
Liu et al. Feasibility study on multi-seam upward mining of multi-layer soft–hard alternate complex roof
Liu et al. Nondestructive testing on cumulative damage of watery fractured rock mass under multiple cycle blasting
Wang et al. Combined effects of fault geometry and roadway cross-section shape on the collapse behaviors of twin roadways: An experimental investigation
Hong et al. The spatial distribution of excavation damaged zone around underground roadways during blasting excavation
Ling et al. Blasting damage of tunnel rock mass based on cumulative effect
Zhao et al. Three-dimensional, real-time, and intelligent data acquisition of large deformation in deep tunnels
CHEN et al. Propagation process of hydraulic fracture crossing an orthogonal discontinuity
Bhuiyan et al. Evaluation of existing tz models for caliche based on numerical analysis of bi-directional load tests using NVShaft
Qiu et al. Failure mechanism of the deep-buried metro tunnel in mixed strata: Physical model test and numerical investigation
Xiang et al. Stability analysis and failure control of a longwall panel with a large mining height considering fracture distribution
Crowder et al. The field-scale rock mechanics laboratory: estimation of post-peak parameters and behaviour of fractured rock masses
Li et al. Improvement of gas drainage efficiency via optimization of sealing depth of cross-measure boreholes
Meng et al. RETRACTED ARTICLE: A Study of Rock Burst Hazard Prevention Method
Xia et al. Numerical study of the mechanism of dense drillings for weakening hard roofs and its application in roof cutting

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2019443098

Country of ref document: AU

Date of ref document: 20191008

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19937506

Country of ref document: EP

Kind code of ref document: A1