神东矿区首层煤炭资源赋存浅、煤层厚、开采强度大，厚松散含水层和薄基岩共存的地质条件导致工作面溃水溃砂事故多次发生。为了研究浅埋薄基岩工作面溃水溃砂致灾原因，采用现场实测、理论分析、相似模拟等方法研究了工作面切顶压架导致基岩裂隙导通工作面与含水松散层的发生机理。建立了覆岩组合承载结构模型，论证了“主控层-软弱层”组合承载结构模型在神东矿区浅埋薄基岩工作面覆岩破断过程中的适用性与合理性，通过组合承载结构模型对神东矿区浅埋薄基岩工作面覆岩组合结构稳定性进行了分析并推导了覆岩组合结构滑落失稳判据，揭示了冲击荷载形成条件并给出了最大冲击荷载计算方法。利用相似材料模拟实验开展了基载比分别为0.625，0.750，0.875，1.125四种工况的相似模拟实验，研究不同“基载比”条件下覆岩结构破坏规律，实验结果表明基载比对主控岩层破断步距的影响方面:初次来压前4类工况中直接顶均发生初次破断冒落，当基载比为0.875~1.150时，直接顶初垮步距及冒落厚度增幅减小;当基载比为0.750~1.125时，初次来压步距呈现增大趋势，直接顶冒落厚度呈现减小趋势;当基载比由0.625增加至1.125过程中周期来压步距呈现明显整体增大的趋势，周期来压相对于初次来压冒落岩层厚度明显减小。基载比对覆岩结构形态的影响方面:当基载比＜0.625时，初次破断期间覆岩将发生贯通至地表的切落;基载比＞0.75时中上位岩层断裂岩块块度为i=0.09~0.50，部分岩层可形成稳定简支结构，覆岩表现为下位冒落、中上位“简支梁-简支梁”组合承载结构，基载比由0.625增加至1.125过程中，对于块度i>0.50的中位岩层断裂岩块，将形成单回转岩块结构，该层位岩块架后切落始终存在，对于块度0.25<i<0.50的上位岩层断裂岩块，将形成简支梁结构，整体覆岩形成协同运动的承载结构，覆岩表现为下位冒落、中上位“单回转岩块-简支梁”组合承载结构，模拟实验结果与理论模型相符。22402工作面初采区域支架实测阻力平均介于5 000~6 000 kN，且来压期间呈现明显的动压显现，支架类型为最大支撑阻力5 500 kN型支架，由于支架性能未能满足实际来压需要导致切顶，基岩裂隙导通工作面与含水松散层，发生溃水溃砂，因此通过适当增加支架阻力可有效防止溃水溃砂事故的发生。

The top seam of coal resources in the Shendong mining area is shallow,the coal seam is thick,and the mining intensity is large.The coexistence of thick loose aquifers and thin bedrock has led to some repeated occurrences of water and sand inrushes in the working face.In order to study the causes of water and sand inrushes in shallow buried thin bedrock,the occurrence mechanism of bedrock fissure conduction working face and water-containing loose layer caused by cutting-top compression frame of working face was studied by on-site measurement,theoretical analysis,similar simulation,etc.Overlying rock combination bearing structure model was built.Applicability and rationality of the “main control layer-weak layer” combined bearing structure model in the overburden breaking process of the shallow buried thin bedrock working face in Shendong Mining Area were discussed.Stability of overlying rock composite structure in shallow buried thin bedrock working face of Shendong Mining Area by combined bearing structure model was analyzed by combined bearing structure model,and the criteria for instability of overburden composite structures was deduced,the impact load formation conditions were revealed and the maximum impact load calculation method was given.In order to study the failure laws of overlying rock structures under different “base-to-load ratio” conditions,the similar simulation experiments with base load ratios of 0.625,0.75,0.875,1.125 were carried out.The experimental results shown the influence of base load ratio on the breaking step of the main rock layer:in the first four types of working conditions for the first time,the first break and fall occurred directly.When the base load ratio was greater than 0.875-1.150,the increase in the initial top step and the step thickness decrease.When the base load ratio was greater than 0.750-1.125,the initial stepping distance would increase,and the direct top fall thickness would decrease.When the base load ratio was increased from 0.625 to 1.125,the cycle step was significantly increased,and the overall step was significantly increased,the thickness of the periodic rock formation was significantly reduced comparing to the initial rock formation.The influence of base load ratio on the morphology of overburden structure:when the base load ratio was less than 0.625,the overlying rock would cut through to the ground during the first break.When the base load ratio was greater than 0.75,the block size of the fractured rock in the upper and middle rock formations was i=0.09-0.50,and some rock formations could form stable and simply supported structures,the lower overburden collapsed,the combined bearing structure appeared in the middle and upper part of the overburden.In the process of increasing the base load ratio from 0.625 to 1.125,a single-revolving rock block structure would be formed for the fractured rock blocks of the median rock formation with a block i>0.5,and the cut-off of the rock blocks at this level always exists.Fractured rock blocks in the upper strata with i<0.5 will form a simply supported beam structure,and the overall overburden would form a coordinated bearing structure,the lower overlying rocks collapse and the combined bearing structure appeared in middle and upper rock formations,the simulation results agreed with the theoretical models.The measured resistance of the bracket in the initial mining area of 22402 working face was between 5 000-6 000 kN on average,and obvious dynamic pressure occurred during incoming pressure.The top plate was cut off by pressure and the working face and the aquifer were connected by fracture channels.Therefore,it is possible to effectively prevent the occurrence of water and sand inrushes by increasing stent resistance.