First fracture characteristics of main roof plate structure with goaf (coal pillar) on both sides and elastic-plastic foundation boundary
CHEN Dongdong;LI Zijian;XIE Shengrong;HE Fulian;LUO Yu;JIANG Zaisheng;MA Xiang;LI Hui
为了研究两侧采空留煤柱工程条件下基本顶板结构的断裂位态及工程指导意义,构建考虑实体煤弹塑性变形与两侧煤柱宽度及支撑能力弱化的基本顶板结构双塑化基础边界力学模型,基于有限差分算法与主弯矩破断准则系统计算了在非对称煤柱区和长边实体煤区的断裂线形态、区位属性及整体位态特征,并从7个层面、横纵向4对区域与传统模型对比,阐明新模型所得新结论及工程意义。结论如下:① 两侧非对称煤柱参数对长边实体煤区域的基本顶主弯矩及破断位置影响小,但分别显著影响煤柱区的主弯矩大小、位置及断裂形态。两侧煤柱区(较强/宽煤柱区+较弱/窄煤柱区)基本顶断裂线形态有3类演化模式,随基本顶厚度及弹模增大而煤柱宽度、支撑能力及悬顶跨度减小,其变化规律为:非对称的“连续单弧形+连续单弧形”→“连续单弧形+开口间断双短弧形”→非对称的“开口间断双短弧形+开口间断双短弧形”。② 长边实体煤区基本顶的断裂线主要有3类区位属性,随基本顶厚度及弹模增大而实体煤的塑性区宽度、塑化程度及悬顶跨度减小,其演变规律为:断裂线在塑性煤体区(C-S式)→弹塑性煤体分界区(C-TS式)→弹性煤体区(C-T式);③ 考虑断裂线区位属性,随基本顶厚度和弹模增大而煤柱宽度、支撑能力及悬顶跨度减小的基本顶全区域破断模式及演变规律为:C-S式的
In order to study the fracture position and engineering significance of the main roof plate structure under the condition of goaf on both sides (coal pillars), the double plasticized foundation boundary mechanical model of the main roof plate structure considering the elastic-plastic deformation of coal and the width and support capacity weakening of coal pillar on both sides is constructed. Based on the finite difference algorithm and the principal moment breaking criterion, the shape characteristics, location attributes and overall position characteristics of the main roof fault line above the asymmetric coal pillars area and the long side solid coal area are systematically calculated, and the new conclusions and important engineering significance of the new model are clarified by comparing with the traditional models from seven levels and four pairs of areas in transverse and longitudinal directions. The conclusions are as follows: ① The asymmetric coal pillars parameters on both sides have little influence on the main roof principal bending moment and fracture position above the long side solid coal area, but significantly affect the principal bending moment, position and fracture shape of the main roof above the coal pillar areas respectively. There are three types of evolution patterns of the main roof fracture line above the coal pillar areas on both sides (strong/wide coal pillar area + weak/narrow coal pillar area). With the increase of main roof thickness and elastic modulus, while coal pillars width, coal pillar bearing capacity and working face span decrease, its evolution law is as follows: asymmetric “continuous single arc + continuous single arc”→ “continuous single arc + open discontinuous double short arc”→ asymmetric “open discontinuous double short arc + open discontinuous double short arc”. ② The fracture line of the main roof above the long side solid coal area mainly has three types of location attributes. With the increase of main roof thickness and elastic modulus, while the plastic zone width and plasticization degree of solid coal and working face span decrease, its evolution law is as follows: the fracture line is above the plastic coal area (C-S type) → elastoplastic coal boundary area (C-TS type) → elastic coal area (C-T type). ③ With the increase of coal pillars width, coal pillar bearing capacity and working face span decrease, and considering the location attribute of the fracture line, the fracture mode and evolution law of the whole area of the main roof are as follows: the mode of C-S (
leftover coal pillar;main roof;goaf on both sides;elastic-plastic foundation;plate structure
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会