摘要:
精确、可靠的开采沉陷预计结果既是井下工作面优化设计、采动损害程度评价的重要依据，也是土地复垦、生态重建设计和老采空区地表再利用稳定性评价的基础。随着实践认识的提高，开采沉陷的研究热点也逐渐从传统的移动稳定的终态预计转向采动地表移动变形的动态预计；当连续6个月累计下沉不超过30 mm时，则认为传统的采动地表移动已经停止，但随着冒落破碎岩石的压实压密导致的缓慢残余下沉仍将持续，且残余下沉的预计也逐渐引起了研究者的重视。基于采动地表移动规律，将采动地表沉陷移动全过程划分为2个阶段：第1个阶段是包括初始期、活跃期和衰退期的地表动态移动变形期；第2个阶段为衰退期结束后的残余下沉期。针对第1个阶段，分析了现有预计方法的优缺点，提出了基于时间函数与概率积分法结合的开采沉陷动态过程预计方法和时空基准，明确指出了只考虑时间而不考虑开采过程进行动态预计、对比验证的错误，强调了终态预计只是动态预计的一个特例，且该动态预计只适用于滞后下沉而不适用于残余下沉的预计。针对第2个阶段，顾及冒落破碎岩石压实压密引起的残余下沉量小，基于衰退期下沉与残余下沉的连续性、残余下沉线性衰减性，给出了给定地质采矿条件下地表残余下沉持续时间和年度残余下沉系数表达式，可以定量计算残余下沉期内任一年度的残余下沉、累计残余下沉和未来潜在残余下沉，实现了采动地表沉陷的全过程预计。针对采动地表沉陷全过程预计方法研究现状，分析提出了动态过程预计存在的计算单元划分、不规则工作面、临近工作面相互影响等问题，以及残余下沉预计存在的诸如冒落破碎岩石压实压密系数、煤柱损伤与垮塌影响、预计的计算范围、预计结果的可靠性与不确定度等问题，为后续进一步研究提供了方向参考。
Abstract:
Accurate and reliable prediction of mining subsidence is not only the important basis for the optimal design of underground work face and the evaluation of surface mining damage, but also for the design of land reclamation and ecological reconstruction, and the reasonable evaluation of the stability and suitability for old mining surface subsidence areas.With the progress of theoretical study and practice, the research hotspot has been changed from the final static prediction to the progressive surface subsidence with time.Once less than 30 mm of accumulative surface subsidence occurs in six months in the weakening period, the traditional surface movement ends, which indicates stabilized surface.However, under the action of the long-term load for overburden rock strata, the residual surface subsidence will continue with the compactions of broken roof rocks, bed separations, and cracks in overburden, considerable attention has been devoted to the subject of the residual subsidence prediction.Based on the law of mining surface movement, the entire process of mining subsidence is divided into two stages.The first stage is the progressive subsidence including initial, active and weakening periods, and the second stage is named residual surface subsidence after the weakening period.For the first stage, the advances and defects are analyzed and the principle of progressive mining subsidence, which is a combined time function and probabilistic integral method, is given.The spatio-temporal datum of progressive prediction for multi-working face mining is proposed.It must be noted that the progressive prediction and comparison are not sufficient only considering the time without underground mining.The final mining subsidence is a special case of progressive subsidence under the condition of time infinity.That is to say that this method is suitable to predict the delayed subsidence at the end of the weakening period but not suitable to predict the residual surface subsidence after the weakening period.For the second stage, based on the continuity of surface subsidence at the end of the weakening period and the residual subsidence in the first year, and a linear monotonic decrease in the residual subsidence factor because of the smaller residual subsidence, the expressions of duration and annual residual subsidence factor are achieved.The quantitative calculation of the duration and annual residual surface subsidence factor can be carried out under the given geo-mining conditions.From the point of view of the current status for the entire process of mining subsidence prediction, the problems of computational element length, irregular working face, and the mining effect of vicinity working faces for progressive surface subsidence are discussed.The existing problems for residual surface subsidence related to compacting factor for broken rocks, damaged and crushed effect of coal pillars, calculating area for prediction, reliability and uncertainty for prediction, etc.are also proposed and discussed.All those problems can be consulted and remain to be solved in the future.
百度学术
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