浅埋房采区下近距离煤层开采动载矿压机理

摘要

The underground catastrophic incidents,such as dynamic mine pressure and support failure,are prone to occur when longwall faces are mined below the upper chamber mining goaf in shallow cover coal seams.Based on a typical case of dynamic mine pressure occurring below the chamber mining goaf in longwall 31201 of Shigetai Mine,the mechanism of this type of dynamic mine pressure has been investigated through field observation,theoretical analysis,experimental and numerical simulations.It is showed that the chamber coal pillar is prone to fail than the concentrated coal pillar;under the influence of mining abutment pressure,the sudden and large-scale failure of chamber coal pillar will break the key strata.The reverse rotation of key blocks transmits the considerable strata load to the lower rock strata structure,resulting in the sliding down of key blocks,which is the primary culprit of the strong dynamic mine pressure occurring in longwall face.Aiming at the similar potential conditions where the dynamic mine pressure is easily to occur,several targeted measures have been proposed from the perspectives of preventing or transferring the upper rock strata load.The effectiveness and practicality of the proposed measures have been demonstrated by their application in longwall 31201.%埋煤层工作面房采区下开采易发动载矿压甚至压架等灾害事故.以石圪台矿31201综采工作面典型房采煤柱下动载矿压的案例为基础,采用现场实测、理论分析、数值模拟和物理模拟手段对此类动载矿压发生的机理进行深入研究.研究结果表明:房采煤柱较集中煤柱更易失稳破坏;在下煤层采动和超前支承压力的影响下,房采煤柱突然大范围的失稳破坏会导致其上方关键层发生超前断裂,关键块体的逆向回转将过大的覆岩载荷传递至下方岩层结构,最终导致下位关键块体发生滑落失稳,这是造成工作面发生强烈动载矿压的根本原因.针对易发此类动载矿压的条件,从阻止或转移上覆岩层载荷的角度提出几点针对性的防治措施,其有效性和实用性得到了31201工作面后续安全开采的证实.