| The Huayingshan is the main part of the paralleled ridge-valley of East Sichuan,which is the ejective fold type composed of parallel box high anticline.The carbonate rock from Cambrian to Triassic is widespread in this area,with distribution area of 987.88km2,and where there are various karst topography.The Longtan coal measures is the main coal seam in Huayingshan,which is one of the major coal producing area in Sichuan province.It is located between P1m+q and P2 c karst aquifers,and difficult to exploit.According to the author’s statistics,there are as high as 87 coal mines in the study area.Furthermore a number of karst water bursting accidents have occurred.On the basis of regional groundwater system theory,this dissertation analyzes karst aquifer system,karst water flow system,and karst water system and its combination relationships with Longtan Coal Measures comprehensively.Using special hydrogeological surveys,geostatistical methods,isotope techniques,hydrogeochemical inverse modeling,tracing test,geophysical exploration technology and other means.The results have scientific significance for minging in Longtan coal measures of Huayingshan area.The main results and conclusions are as follows:（1）The total distribution area of carbonate rock is 987.88km2,including Triassic（T）,Permian（P）,Ordovician（O）,and Cambrian（?）formations.The Triassic is composed of thick layer of pure limestone and dolomite,accounting for 80.71% of the total area.The Permian consists of thick limestone and thin inclusions of argillaceous limestone,and accounting for 16.33% of the total area.The Ordovician mainly contains homogeneous limestone and interlayerded marl and Cambrian mainly contains pure dolomite,accounting for 1.71% and 1.25% of the total area,respectively.（2）Karst development is plentiful and form diversely with a total of 2061 karst points in the study area,73.78% of the 633 karst depressions and 79.87% of the 477 sinkholes are distribution in the elevation 6001000m.80.47% of the 768 dolines and karst shafts and 73.77% of 183 karst caves are distribution in the elevation 6001100m and 400900m,respectively.The karst development intensity of carbonate formation is in sequence of T1j>T1f>P1m+q>P2c+P2l>O>?2-3ls.（3）The karst media is divided into 2 basic types—conduit type and fracture type.Combined with the combination features of media forms,the media structures can be classified into pure conduit-fracture type,interlayer conduit-fracture type and fracture type.The total dustribution area of pure conduit-fracture type is 872.73km2,including T2 l,T1j,T1f2+4,P1m+q,O1t+h and ?2-3ls karst aquifer.The total dustribution area of interlayer conduit-fracture type is 115.15km2,including P2 c,P2l2+4 and O2-3 karst aquifer.The fracture type is distributed in each karst aquifer.The water abundance of karst aquifer can be classified into 3 grades— strong water abundance aquifers,middle water abundance aquifers and weak water abundance aquifers.Their distribution area of 3 grades is 848.91km2,133.64km2 and 5.33km2,respectively.Combined with the geological structure conditions,the karst water storage structure is divided into 3 types— anticlinal type,syncline type and compound type.The flow mode of karst water is along-axial-flow and vertical-axial-flow,the former is often form underground river flow zones and the latter is form inverted siphon flow.（4）In the study area,atmospheric precipitation and surface water are main recharge sources.Pipelines and fissures are main flow channels.Karst spring,underground river and artificial drainage are major discharge forms.The vertical karst water flow is divided into epikarst zone,unsaturated zone,seasonal exchange zone,saturated zone,pressure saturated zone and deep slow flowing zone,while the vertical hydrodynamic zonality of karst is divided into 3 models,single structure model,compound structure I and compound structure II.Shaft tunnels are located in the seasonal exchange zone and saturated zone,and coal tunnels are located in the pressure saturated zone.The karst hydrodynamic model is divided into 2 categories and 6 subtypes.The flow type of karst water in anticline control and syncline control are divided into 3 types respectively on the basis of flow characteristics.Summarizing the Huayingshan karst water system conceptual model according to the characteristics of karst aquifer system,karst water flow system,analyzes of hydrochemical characteristics and hydrological cycling,and anatomical karst water subsystem.（5）The karst aquifer is divided into direct water filling aquifer and indirect water filling aquifer according to the water filling characteristics of the coal seam.The former includes P1 m and P2 l floor direct water-filling aquifers,and the latter includes P2 c,T1f,T1 j,T2l and other karst aquifers.P2 c karst aquifer is the greatest threat to coal seam.The occurrence forms of coal mesures are upright or upside down,repeated or missing,local variation of thickness,and destroy coal seam continuity,which is controlled by decollement pattern of Huayingshan compound structures.The combination relationship of coal measures and karst water system is divided into 4 categories and 5 subtypes— monoclinic structure type（I subtype and II subtype）,syncline structure type,fault block tectonics type,and composite tectonics type.In the Longtan Coal area,through plotting karst water flow field and water level contours of P2 c and P1 m karst aquifer under both natural and artificial drainage conditions,analyzing the relationship of coal minging and karst water flow system evolution process.The karst water flow system under natural condition is hierarchical.The karst water flow system is evolving continuously and appearance a sub-watershed between water inrush points and karst spring under artificial drainage condition,and sub-watershed gradually moved out with drainage process.Based on above,the ununity and hierarchical of karst water system are enhanced and weakened/ disappearing.（6）This dissertation mainly study the water bursting disaster in the Longmen Gorge South Coal Mine +623m ventilation adit,and analyse discrimination of water bursting source and underground flowing paths detection.The results of discrimination of water bursting source shows that has similar relations betweent monitoring points M1 and & M2 and karst springs S3 and & S5,and it has hydraulic connections with injection point T2.Especially monitoring point M1,it has larger homologous possibilities with S3,and larger connected possibilities with injection point T2.Both of inlet and outlet of flowing paths are located at P2 c karst aquifer.The results of underground flowing paths detection shows that it has 20 densely fracturesfissure densely develop zones,5 large new caves,and 2 water conductive faults.,also the connectivity and hydraulic interactions between cave 6# and underground river in +623m ventilation adit could be proven.In general covering the range of 540660m can be considered as strong karst dissolution area,which mostly located in P2 c karst aquifer and has hydraulic connections.（7）The karst water bursting passage can be divided into two types: water bursting from fault zone and water bursting caused by karst collapse pillar,founding that fracture is the basic element of the formation of water bursting passage,in which the fractures of T1 f,P2c and P1 m formation are the most typical examples,and they penetrate both the upper and lower aquifers,which have a great influence on the water filling of coal seam.The open faults can be regarded as water filling and water conducting faults which are the main passages of water bursting.The closed faults can be transformed into the open faults under hydrostatic pressure and rock pressure in mine.The P2 c and P1 m form a large number of karst collpase pillar,which have obvious zoning and banding features.The karst collpase pillar in P2 c formation are the main water bursting passage that can penetrate both the upper and lower aquifers,and can be formed the main water bursting passage when connected with the caving zone.When the destroying depth of coal seam floor connected with the collpase pillar expansion crack in P1 m under mining conditions,it can also cause water seepage or water bursting. |
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