Design and safety of advance detection and drainag

2022-08-01
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Design and safety technical measures for advanced detection, water exploration and drainage of working face and floor drainage roadway

11051 task face roadway is located at the level of 0-80, which is primarily used as the replacement of 11061 task face. The inclined length of the cutting roadway is 120m, the azimuth is 356, and the excavation is carried out along the No. 21 coal seam. The inclination angle is -26, and the thickness of the coal seam is 3.2m; The opening of the upper auxiliary lane of the task face is located in the west of the seventh Lane parking lot turning back to the downhill. The elevation of the opening is -37.1m. It mainly deals with the air inlet and transportation, air return and material transportation of the 11051 task face; The upper roadway is designed to be excavated along the goaf of 11031 task face, with a total length of 876m, a total bearing of 266, a slope of +3; The lower auxiliary lane of the task face is located to the west of the belt downhill of Lane 8, with an opening elevation of -91m, a design orientation of 266, a slope of +3, and a total length of 1040m

11051 the driving task face of the floor extraction roadway of the lower auxiliary roadway is located in the west of the mining area pump room. The opening elevation of the roadway is -79.6m. After the opening, the roadway is driven down the hill at -29. After the roof of the roadway enters coal seam 18, it is driven along coal seam 18. The orientation is 266, and the gradient +3 task face is 945m in total. The upper roadway floor extraction roadway is located 632 meters west of the 11051 upper auxiliary roadway opening, with an opening elevation of -18m. After opening, it is driven down the hill at -23. After entering coal seam 18, it is driven along coal seam 18, with an orientation of 266, a gradient of +3, and a total length of 230 meters. Anchor bolt shotcreting support is adopted for both sections of the extraction roadway, and the designed net excavation section is 10.5m2

minimum 179.30n

according to the court review of "mining under pressure" of No. 21 coal seam by Zhengzhou coal industry personal limited company, the Enron Technology Office concluded that when our mine mines No. 21 coal seam between -65 and -100m elevations, the normal block is Enron, and there is a risk of water inrush from the floor of the water rich area or the large block of the floor mechanism. Therefore, in some sections with huge water inrush risk between -65 and -100m elevations, we must insist on "geophysical exploration first and drilling verification" Level line for exploration and setting out

(I). Drilling design of 11051 upper and lower roadways and cutting roadways

① the 11051 upper and auxiliary roadways are excavated from east to west. During the excavation process, water exploration and drainage are stopped for the goaf on the upper side of the roadway. The design depth of drilling is 60m, the safe lead distance is 20m, and the upper side distance is controlled by 30m. It is allowed to dig 40m to win market share by relying on technical resources and customer advantages. Every 40m is a cycle. It is planned to explore and drain water 21 times, and dig 851m of the roadway; The 11051 lower auxiliary roadway is excavated from east to west, and the 11051 bottom extraction roadway pumping hole and advance detection hole are used as the 11051 lower auxiliary roadway water exploration and drainage hole

② the secondary exploration and water drainage of 11051 lower auxiliary roadway will not be stopped, but the physical exploration of 11051 lower auxiliary roadway must be stopped by DC instrument. The detection interval is 60m, and the safe lead distance is 20m. It is allowed to excavate 40m. Every 40m is a cycle. It is planned to perform 24 times of physical exploration and excavate 1040m of roadway

③ the cutting roadway of the 11051 task face is excavated from top to bottom. The designed drilling depth is 60m, the safe lead distance is 20m, and the distance between the East and west sides is controlled to be 20m respectively. It is allowed to excavate 40m. Every 40m of excavation is a cycle, and it is planned to explore and release water for 4 times

11051 upper and auxiliary roadway water exploration and drainage drilling design parameters

zy-750 water exploration drilling rig is adopted, and the drilling rig is intact and can be used normally

the hole diameter is Φ 118mm, 11m deep, casing Φ 108mm seamless steel pipe 10m. The outer end of the orifice pipe is welded with a flange plate and connected with the valve. The outer end of the orifice pipe is welded with a firm ear handle and tied firmly with the column support. Cement grouting is used to fix the pipe to increase the friction force, and the berm is used to firm the pipe to prevent the casing from bulging out. The pressure resistance of the valve is greater than 2MPa. During the construction of drainage holes, the number and parameters of drainage holes can be adjusted appropriately according to the coal seam exposure environment and roof environment, and the number of drilling cycles can be increased. Coreless drilling is adopted for all boreholes. During the construction process, it is necessary to probe while drilling. The drilling hole shall guarantee a lead distance of 30 meters

(II). The design of advanced detection and water exploration drilling holes for 11051 bottom extraction roadway

①. Six boreholes are designed. Among them, holes 4, 5 and 6 are bottom water exploration drills, and holes 1, 2 and 3 are coal seam exploration holes. The final holes are located 20, 40 and 60m in front of the roadway, with a depth of 30 meters from the roadway bottom. It is proved that 40m can be drilled in front of the roadway without water inrush risk, and a lead distance of 20m can be guaranteed

technical parameter table of advance detection and water exploration drilling

the above parameters shall be adjusted at any time according to the detected coal thickness of each drilling yard and the roadway top interval II 1 coal seam interval

② drilling construction process

use zy-750 drilling rig to jointly Ф 94mm drill bit, Ф 63mm drill pipe, full hole coreless drilling, water discharge of pulverized coal in rock section and air discharge of pulverized coal in coal section

the water exploration borehole must be drilled into L1 ~ 3 limestone, and the grouting dispersion radius is estimated to be 15 m. The orifice pipe is divided into two-stage devices. The first stage orifice pipe is lowered into the bottom plate less than 8 m, with a diameter of 127mm, and the second stage orifice pipe is 110mm, with a depth of not less than 15 m below the bottom plate. Stop cement grouting for reinforcement

② supply and drainage, water supply and drainage system

the drilling site must have excellent power supply, ventilation and water supply and drainage system. The water supply volume of the drilling rig shall not be less than 5m3/h; The water is discharged to the water sump of the mining area through the pump. A public telephone system must be set around the drilling yard so as to timely contact with all business departments in the air

③ technical requirements for drilling construction

the construction unit must strictly follow the design and construction. The drilling direction shall be calibrated by the geological survey department, and the slope shall be calibrated by the construction unit itself. It shall not be changed at will during the construction process. If there is a change due to the Limited demand of on-site construction, it must be approved by the geological survey department. At the same time, the single hole design shall be changed according to the on-site change environment and a construction notice shall be issued

if the drilling water pressure in this roadway is large, in order to ensure the safety of construction personnel, blowout prevention and back pressure assembly such as blowout prevention and orifice drill pipe holder must be used to prevent the drilling tool from being pushed out by high-pressure water and injuring people

the opening horizon is sandy mudstone, which is liable to soften and shrink in case of water. During the drilling construction, hole collapse and borehole shrinkage can occur. Therefore, the hole for casing running shall be enlarged to the greatest extent. The drilling shows how much load will bend by 1mm. The flushing water shall be supplied by the grouting pump equipped with the drilling rig instead of the air water supply directly, so as to prevent the crushing of the hole wall by the high-pressure water. At the places where the hole wall is relatively broken, the drilling can be carried out after pressure grouting reinforcement

make on-site small shift record, which shall meet the requirements of "timely, accurate, complete and clear". Accurately record the initial water volume, maximum water volume, stable water volume and water pressure of each aquifer, rock stratum, name, aquifer depth, karst development degree and location after entering the aquifer, and make simple and simple hydrological survey and record, so as to facilitate the collection and analysis of data

according to the water pressure of 3.1Mpa, a drilling lead distance of 30m shall be reserved. The first stage casing is designed to be 5m below the roadway floor, and the second stage casing is designed to be 15m below the roadway floor. Cement grouting shall be used to firm the casing, and the outer end of the casing shall be welded with a flange and equipped with a gate valve. The pressure test pressure of casing at all levels shall not be less than 4.6mpa, and the grouting pressure of the final hole shall not be less than 7MPa, and the duration shall not be less than 30 minutes. If there is water leakage in the drilling hole, re grouting shall be carried out, and the pressure test shall be stopped again until the orifice pipe meets the pressure test requirements. The pressure of the pressure test shall not be less than the design grouting final hole orifice pressure, and it must be resealed if it is unqualified

④ grouting process

the detection, reinforcement, hole sealing and reinforcement casing of the roadway floor are mainly composed of water glass, cement and water. The grouting reinforcement is mainly composed of single liquid slurry and cement and water. The grouting generally adopts the method of continuous grouting in the whole section, continuous grouting by holes and times until the final hole pressure is reached. The goal is to drive the lead screw pair to load and fill karst fissures after the maximum amount of grouting, the maximum range of dispersion, and the maximum limit of charging and deceleration. If the water inflow of a single hole is greater than 20m3/h, a grouting verification hole must be added on both sides of the hole after the grouting is completed. The water inflow of the final hole of the verification hole shall not be greater than 10m3/h. Otherwise, the grouting treatment shall be continued until the water inflow of a single hole is less than 10m3/h, and the cement sealing of the final hole of the anhydrous hole shall be stopped

⑤ single hole grouting completion standard and grouting result inspection

single hole grouting completion standard: the greater the grouting pressure is, the greater the dispersion range is, the more sufficient the crack is filled, and the higher the strength of the strong body is formed. However, when the pressure exceeds the inevitable limit, it is easy to form roadway floor heave and slurry running. Therefore, the completion standard of single hole grouting is: the pump capacity is less than 80l/min, the orifice pressure shall not be less than 2.5 times of the water pressure, and the duration is more than 30 minutes. However, in case of roadway floor heave or large amount of slurry leakage, intermittent method or adjusting slurry specific gravity and grouting parameters can be adopted to stop plugging. After the completion of drilling and grouting, the water inflow of a single hole shall reach 10m ⊃/H. The construction of the second inspection hole shall be stopped, and the maximum water volume of the inspection hole shall not exceed 5m3/h

3. Acceptance method

(1) Opening acceptance

the chief engineer of the mine shall organize all production parts to stop drilling. After passing the acceptance, it shall be reported to the geological survey and water prevention department of Songyang company for consent. The drilling can be stopped before

(2). Final hole acceptance

before the advanced detection drilling and water exploration drilling meet the design requirements and the final hole is stopped, the geological survey and water prevention office and the office of Songyang company shall be informed in a timely manner. Songyang company shall stop the return drilling acceptance of the final hole according to the task requirements. If Songyang company does not stop the on-site acceptance, the mine shall organize the relevant production parts to stop the final hole acceptance

4. Enron technical measures

(I) Enron technical measures for 11051 floor drainage roadway

(1) The geological survey section staff will set out the borehole orientation and inclination in the drilling yard. The sampling team shall carry out construction in strict accordance with the line, and shall not change without the consent of the technical staff

(2). Before drilling, the drill must be stabilized and aligned with the azimuth and inclination of the drill before construction. During the drilling process, the drilling crew must record the drilling progress and the rock stratum change environment

(3). When opening and closing the switch, pay attention to the concentration of vision, ensure that the hand is not away from the button and the eye is not away from the drilling rig, observe and obey the orders of the drilling rig driver at any time, and start and close the switch accurately, timely and quickly

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