巷道层状组合底板在垂直压力下的底鼓研究

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1、巷道层状组合底板在垂直压力下的底鼓研究StudyonHeavingMechanismofLayeredCombinationRoadwayFloorunderVerticalPressure摘要巷道底板岩层组合结构是巷道底鼓的根本性内因之一，决定着在垂直压力作用下，巷道底鼓类型及底鼓变形量。本文利用弹性地基梁理论、组合梁理论，建立了巷道底板力学模型并对巷道的底鼓影响因素进行了理论推导、分析；采用FLAC3D数值计算和相似模拟实验相结合的研究方法，对“硬-软-硬”巷道底板岩层组合在层厚、强度、巷道跨度差异时在垂直压力下的底鼓量、应力进行对比分析。得到的有益结论为：巷道底

2、鼓量与巷道底板岩层组合关系密切，底鼓主要影响因素为硬岩厚度、临近软硬岩层层厚比、巷道跨度、煤层强度。（1）巷道底板硬岩厚度的增大及软岩厚度的减小，对巷道底鼓现象的减弱起着关键性作用；（2）煤层强度的提高，围岩抗剪强度提高，可减小巷道的两帮移近量，移近量的减小大大减弱了煤层移动对底板的水平面力，进而对底鼓影响减小。（3）采用物理实验研究了垂直压力对巷道底鼓的影响：底板“硬软硬”岩层组合下，随压力逐渐增加，底鼓由挠曲型底鼓逐渐转变为软岩膨胀型底鼓，底板薄硬岩层受压折断成为底鼓类型转变时机。（4）巷道跨度增加，底板不同位置处变形量均增大；巷道跨度增大，煤帮塑性区增大，煤壁对

3、下方底板的压模作用及位移约束减弱，底鼓量增大。该论文有60幅图，表9个，参考文献63篇。关键词：底鼓机理；岩层组合；硬-软-硬结构；影响因素AbstractThecompositestructureoffloorstratainroadwayisoneofthemostfundamentalinternalcauseforthefloorheave,itdeterminesthetypeanddeformation7offloorheaveundertheeffectofverticalpressure.Inthispaper,thetheoryofelasticfo

4、undationbeamandcompositestructurebeamhavebeenusedtoestablishthemechanicsmodeloftheroadwayfloor,evenmore,factorsoffloorheavehavebeenderivedandanalyzedontheory;the"hard-soft-hard"combinationofroadwayfloorrockinthelayerthickness,strength,thetunnelspandifferencesintheamountoffloorheaveunder

5、theverticalpressureandstresshavebeenanalyzedandcomparedbysyntheticallyusingFLAC3Dandnumericalsimulation.Theconclusionsareasfollows:theamountoffloorheaveofroadwayiscloselyrelatedtocompositefloorstrataofroadway,andthemaininfluencefactorsarethethicknessofhardrock,theratiooflayerthicknessbe

6、tweenthehardandsoftrockclosetoeachother,thespanofroadway,thestrengthofcoalseam.(1)Theincreaseonthicknessofhardrockinfloorofroadwayandthedecreaseonthicknessofthesoftrockplaysakeyroletoweakthephenomenonthefloorheaveofroadway.(2)Withtheincrementofthestrengthofcoalseam,surroundingrockshears

7、trengthincrease,anditcanreducetheamountsoftwosidescloser,thedecreaseofclosergreatlyreducedthelevelofthehorizontalforceforfloorofcoalseam.Asaresult,theinfluencetothefloorheaveofroadwaywilldecrease.(3)Thefloorheaveofroadwayunderverticalpresshavebeenresearchedandanalyzedbyusingphy