Experimental Study On The Technology Of Instant And Automatic Construction Of Floodgate Wall In Mines

Floodgate wall is an important and effective measure to prevent the further expansion of mine water disaster.It has been widely used for its high economy and practicability.However,at home and abroad,there are no any kinds ofeffective ways to stop immediatelythe spread of water disaster and to save more timeto escape for people,resulting in a lot of underground workers losing their lives.In this paper,the mechanical tests of floodgate wall filling materials,forming and fixing technology,mobile technology,instant filling technology and automatic controltechnology were experimented.The resistance to water pressure of instant and automatic construction of floodgate wallwas calculated.The construction conditions of floodgate wallwere analyzed.Finally,the system of instant and automatic construction of floodgate wall with laboratory scale has been developed.Through experimental study on mechanics of building materials,the mechanical parameters such as the compressive strength,shear strength,Young's modulus,Poisson's ratio,cohesive force and internal friction anglewere got,when materials are in 3,5,7 and 9 of the expansion ratio.In this paper,according tothe method of orthogonal experiments,the analogueexperiments with 1:100 ratio of real conditions in the roadway were conductedby filling with solid or liquid materials.At last,we got a set oftechnology of instant and automatic construction of floodgate wall for the system installing,opening,filling,fixing,moving and so on.The important parameters such as buildingspeed,water blocking resistance and water plugging rate were obtained.The experiments show that the floodgate wall filled in the liquid material begins to take effect in 36-185 s under the expansion pressures of 0.5-0.6MPa,and that thewater plugging ratesare 78%-90%.In contrast,the time that floodgate wallfilled in the solid material takes effect is 185-240 s under the expansion pressures of 0.25-0.3MPa.The water plugging ratesare60%-73%.Comparison of the two groups of the data shows that floodgate wall filled in liquid material is better in water plugging effect than that filled in solid material;water plugging effect of floodgate wall under the condition without the belt rack is better than that with belt rack.Based on the study of resistance calculation,two kinds of floodgate wall structures ofwedge and rectangle models were proposed,and the formulas for calculating the floodgatewall length of two kinds of models were derived.The results show that the construction materials ofthe expansion ratio of 5 or 7 can be used for block goaf water inrush under the pressure less than 0.5MPa;that the construction materials of the expansion ratio of 3 can be used to block water inrush from collapse column under the pressure of 3.5MPa.The construction conditions such as surrounding rock conditions,the application conditions and the construction technology of the floodgate wall were studied.It is considered that the siteof the floodgate wall should be intact enough in rock structure,of high mechanical strength and of low permeability.Surrounding rocks of floodgate wall should be artificially reinforced if it fails to meetthe above conditions.The paper holds that the instant and automatic construction of floodgate wall of the expansion ratio of 5 or 7 can be used to control goaf water inrush of lower water pressure,the expansion ratio of 3 can be used to control collapse column water inrush of the water pressure of 3.5MPa.