异形载荷–弹性基础基本顶板结构破断特征及稳定性分析  

Fracture characteristics and stability analysis of main roof plate structure with special-shaped load and elastic foundation

作　　者：吕凯 何富连[1,2] 许旭辉 翟文立 秦宾宾 LV Kai;HE Fulian;XU Xuhui;ZHAI Wenli;QIN Binbin(School of Energy and Mining,China University of Mining and Technology(Beijing),Beijing 100083,China;Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources,China University of Mining and Technology(Beijing),Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)能源与矿业学院,北京100083 [2]中国矿业大学(北京)共伴生能源精准开采北京市重点实验室,北京100083

出　　处：《岩石力学与工程学报》2023年第4期930-947,共18页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51974317);中央高校基本科研业务费专项资金资助(2021YJSNY01)。

摘　　要：为了研究近距离煤层层间基本顶三维破断演化特征,建立异形载荷–弹性基础基本顶板结构周期破断力学模型,探究不同载荷作用下层间基本顶破断位置、破断类型和破断形态,并对破断结构进行空间稳定性分析,阐明直角梯形板块失稳灾变条件及其对主控因素的响应规律。结论如下:(1)基本顶破断形态与上覆载荷分布形式直接相关,在均布载荷作用下,基本顶发生“O-X”破断,形成1个类等腰梯形板块和2个弧三角块体;在边界煤柱–采空区单峰状载荷作用下,基本顶发生“■”破断,形成2个类直角梯形板块和2个弧三角块体;在孤岛煤柱驼峰状载荷作用下,基本顶发生“■”破断,类直角梯形板块间形成块裂区。(2)破断结构失稳判据显示,直角梯形板块存在滑落失稳和回转变形失稳2种失稳形式,且每种失稳形式具有整体失稳、单边失稳和不失稳3种灾变组合。(3)随上覆载荷q增大,滑落失稳系数(深入煤体长边K1、侧向直角边K2)减小,回转失稳系数(深入煤体长边K3、侧向直角边K4)增大,即载荷增大不利于板块保持稳定;板块断裂宽度w具有与载荷q类似的规律,但当断裂宽度达到一定值以后,板块稳定性对其敏感程度降低;来压步距l增大,滑落失稳系数(K1,K2)及回转失稳系数(K3,K4)均增大,即来压步距增大容易诱发回转失稳;下煤层采高m2增大,滑落失稳系数(K1,K2)减小,回转失稳系数(K3,K4)在回转末期显著增大,即下煤层采高增大不利于板块稳定。(4)现场矿压监测及钻孔窥视结果在一定程度上验证了力学模型及理论分析的合理性与可靠性。In order to study the three-dimensional fracture evolution characteristics of the main roof between adjacent coal seams,a mechanical model for the periodic fracture of the main roof plate structure with special-shaped load and elastic foundation was proposed to analyze the fracture position,fracture type and fracture pattern of the main roof.Moreover,spatial stability of the fracture structure was analyzed to discuss the instability conditions of the right-angle trapezoidal block and its response to the key factors.The results were as follow:(1)The fracture characteristics of the main roof are directly related to the distribution of the overlying load.When the load is uniform,an“O-X”shaped fracture appears on the main roof,which forms an isosceles trapezoidal block and two arc triangular blocks.When the roof is subject to a single peak load formed by boundary coal pillar and goaf,an“O-■”shaped fracture appears on the main roof,which forms two right-angle trapezoidal blocks and two arc triangular blocks.Meanwhile,when the roof is subjected to a bimodal load formed by isolated coal pillar,the fracture pattern of the main roof takes an“O-■”shape,thereby forming a crushing zone between the right-angle trapezoidal blocks.(2)According to the instability criterion of the fracture structure,instability forms of right-angle trapezoidal block include sliding instability and rotation instability,and each form can be divided into overall instability and one-side instability.(3)As the overlying load(q)increases,the sliding instability coefficient(K1 and K2)decreases,while the rotation instability coefficient(K3 and K4)increases,indicating that the increase of load(q)is not conducive to the safety of surrounding rocks.The law of the fracture width(w)is consistent with the overlying load(q).However,when the fracture width reaches a certain threshold,the sensitivity of block stability decreases.As the cycle weighting interval(l)increases,the sliding instability coefficients(K1 and K2)and the rotation instability

关 键 词：采矿工程 近距离煤层 基本顶 板结构 载荷分布 弹性基础 周期破断 结构失稳 

分 类 号：TD32[矿业工程—矿井建设]