【作者】 张欢；

【导师】 陈应涛； 朱伟；

【作者基本信息】 西安科技大学 ， 地质工程（专业学位）， 2023， 硕士

【摘要】 岩溶陷落柱突水是华北地区石炭-二叠系煤田主要的水害类型之一,严重威胁煤矿安全生产。韩城矿区作为我国华北石炭-二叠系煤田西南部重要的煤炭生产基地,认识其岩溶陷落柱发育的主控因素及其特征,探讨明晰韩城矿区岩溶陷落柱的发育过程,不仅能为韩城矿区岩溶陷落柱防治工作提供理论依据,进一步为矿井安全生产提供地质保障,更深层次上可为探索华北型岩溶陷落柱发育机理提供新的思路和基础。本文以韩城矿区岩溶陷落柱为研究对象,在野外踏勘和井下观测的基础上,结合钻探、物探及实际生产资料,采用野外构造解析、岩矿鉴定、构造物理模拟、地球化学、古地貌分析等方法,分析了岩溶陷落柱的发育特征与主控因素及其特征,探讨了其发育过程。主要成果如下:(1)韩城矿区已探明陷落柱15个,其中实际生产揭露2个,钻探探查疑似陷落柱1个,物探圈定12个,均位于北区,平面形态多为椭圆形,已揭露陷落柱柱体内主要为杂乱煤系,可见方解石等结晶体,不含水,向上终止于煤层顶板,两壁陡立,邻近构造发育部位。研究区岩溶陷落柱发育主控因素包括可溶性岩层、构造地质条件和古水文地质条件。(2)中奥陶统马家沟组五段(O2m5)和六段(O2m6)下部是研究区最易发育岩溶的主要层位,为岩溶陷落柱的发育提供了有利的物质基础,其岩性主要为厚层块状白云岩和粉晶石灰岩夹白云岩,次生孔隙较为发育,显微镜下常见晶间孔、粒内孔、裂缝等,是在氧化、干热气候、较高水温、较浅水体的有陆源物质影响的近岸沉积环境中沉积而成,沉积相主要为潮坪沉积。韩城矿区自加里东期以来多期次构造活动形成的断层、褶皱、节理等构造及其组合和多阶段地壳升降运动为岩溶的发育提供了有力构造地质条件,尤其是新生代的伸展构造是岩溶坍塌的主导因素。自奥陶系沉积以来研究区内发育岩溶高地、岩溶台地、岩溶浅谷及侵蚀沟槽等地貌单元,其中最为典型的则是形成的NE-SW向侵蚀沟槽,其尾端发育的古岩溶凹地至今仍存留残迹,该沟槽的发育在一定程度上控制了岩溶陷落柱的形成位置,可能为韩城矿区北区发育岩溶陷落柱,而南区不发育的控制性因素之一。(3)韩城矿区岩溶陷落柱发育过程主体经历了五个阶段:①同生期和风化壳岩溶发育阶段,奥陶系在沉积过程中受大气降水淋滤和地表水溶蚀等作用形成岩溶,并于加里东期接受风化剥蚀发育风化壳型岩溶。②印支期岩溶停止发育阶段,自古生代晚石炭世到中生代中三叠世末,受区域性沉降影响奥陶系深埋,岩溶作用减弱或基本停止。③燕山期岩溶发育格局的改造阶段,在NW-SE向挤压应力作用下,研究区发育逆断层、褶皱和共轭节理,促进了岩溶水通道的连通性,岩溶作用进一步发育。④古近纪岩溶垂向发育形成阶段,随着研究区地壳的快速抬升,垂向溶蚀快速发育扩大。⑤新近纪陷落柱形成阶段,前期形成的岩溶空洞经伸展运动改造导致岩溶空洞垮塌,从而形成了岩溶陷落柱。更多还原

【Abstract】 Karst collapse column water inrush is one of the main water hazards in the Permian Carboniferous coalfield in North China,which seriously threatens the safety of coal mine production.Hancheng mining area is an important coal production base in the southwest of the carboniferous Permian coalfield in North China.Understanding the main controlling factors and characteristics of the development of karst collapse columns in Hancheng mining area,and discussing the development process of karst collapse columns in Hancheng mining area can not only provide theoretical basis for the prevention and control of karst collapse columns in Hancheng mining area,but also provide geological guarantee for mine safety production.At a deeper level,it can provide a new idea and foundation for exploring the development mechanism of North China type karst collapse column.In this paper,the karst collapse columns in Hancheng mining area are taken as the research object.On the basis of field exploration and underground observation,combined with drilling,geophysical exploration and actual production data,the development characteristics and main controlling factors of karst collapse columns are analyzed by field structure analysis,rock and ore identification,structural physics simulation,geochemistry and paleogeomorphology analysis,and the development process is discussed.The main achievements are as follows:(1)15 collapse columns have been identified in Hancheng mining area,of which 2 have been revealed in actual production,1 suspected collapse column has been explored by drilling,and 12 have been delineated by geophysical prospecting.All of them are located in the north region,and their plane shape is mostly oval.The collapse column body has been revealed to be mainly chaotic coal measure strata,visible calcite crystals,no water,and terminated upward at the coal seam roof with two steep walls.Adjacent structural development site.The main controlling factors of karst collapse column development in the study area include soluble rock strata,tectonic geological conditions and paleohydrogeological conditions.(2)The soluble rock strata in the study area are mainly the Ordovician Yeli Formation(O1y),Liangjiashan Formation(O1l)and Majiagou Formation(O2m)in the lower part of the coal measures.The lower part of the 5th member(O2m5)and the 6th member(O2m6)of the Middle Ordovician Majiagou Formation is the main bedding that is easy to develop karst in the study area,which provides favorable material basis for the development of karst collapse columns.The lithology is mainly composed of thick massive dolomite and silty limestone with dolomite.The secondary pores are relatively developed,and the common intergranular pores,intra granular pores and fractures are observed under the microscope.It is deposited in the coastal sedimentary environment affected by terrigenous materials in oxidizing,hot and dry climate,high water temperature and shallow water.The sedimentary facies is mainly tidal flat deposition.The fault,fold,joint and other structures and their combinations formed by multistage tectonic activities since Caledonian and multi-stage crustal movements in Hancheng mining area have provided powerful tectonic geological conditions for the development of karst,especially the Cenozoic extensional structure is the dominant factor of karst collapse.Since Ordovician sedimentation,karst plateaus,karst valleys and erosion trenches have developed in the study area,the most typical of which is the NE-SW erosion trench,and the paleokarst depression developed at the tail end still has remnants.The development of the groove controls the formation position of the karst collapse column to a certain extent,which may be one of the control factors for the development of karst collapse columns in the northern area of Hancheng mining area and the non-development of southern areas.(3)The development process of karst collapse columns in Hancheng mining area has experienced five stages:①syngenetic stage and weathering crust karst development stage,the Ordovician strata were formed by atmospheric precipitation leaching and surface water dissolution during the deposition process,and weathering denudation developed weathering crust karst in Caledonian period.②The Indosinian karst stopped developing stage.From the late Carboniferous of Paleozoic to the end of Middle Triassic of Mesozoic,the Ordovician strata were deeply buried under the influence of regional subsidence,and karstification weakened or stopped basically.③ In the reform stage of karst development pattern in Yanshanian,under the action of NW-SE compression stress,reverse faults,folds and conjugate joints developed in the study area,which promoted the connectivity of karst water channels and further developed karst processes.④In the vertical development and formation stage of Paleogene karst,the vertical dissolution rapidly developed and expanded with the rapid uplift of the crust in the study area.⑤ In the formation stage of the Neogene collapse column,the karst cavity formed in the early stage collapsed after extension movement reconstruction,thus forming the karst collapse column.更多还原