CN212535755U

CN212535755U - Goaf filling structure

Info

Publication number: CN212535755U
Application number: CN202020767769.7U
Authority: CN
Inventors: 郭建湖; 孙红林; 庞吉鸿; 詹学启; 李巍; 姚洪锡; 孟祥龙; 贾厚华
Original assignee: China Railway Siyuan Survey and Design Group Co Ltd
Current assignee: China Railway Siyuan Survey and Design Group Co Ltd
Priority date: 2020-05-11
Filing date: 2020-05-11
Publication date: 2021-02-12
Anticipated expiration: 2030-05-11

Abstract

The utility model provides a collecting space area filling structure, it includes the tunnel obturator and ends the thick liquid dam body, ends the thick liquid dam body and extends along the direction of depth in collecting space area, ends the thick liquid dam body and sets up in the week side of tunnel obturator in order to form the curtain, ends the thick liquid dam body and is filled by the concrete and form. According to the goaf filling structure, the slurry stop dam body is arranged in the depth direction of the goaf, and the slurry stop dam body is arranged on the periphery of the roadway filling body to form a curtain wall, so that a completely closed effect is achieved, and the filling material can be prevented from being greatly lost in the process of forming the roadway filling body; the grout stopping dam body is formed by pouring concrete, a grout stopping curtain can be formed more effectively, and the problem of high difficulty in goaf treatment is solved.

Description

Goaf filling structure

Technical Field

The utility model relates to a geological disasters administers technical field, in particular to collecting space area filling structure.

Background

In the treatment of the goaf, the situation that the goaf cavity is large or a roadway is full of water is often encountered, the treatment range of the goafs is large, the depth is deep, the width of the roadway is wide, and the traditional grouting treatment method has certain defects, such as large outer space of the goaf treatment boundary, good mutual connectivity, uncontrollable grouting material flow and the like, which easily causes a large amount of slurry to flow out, and causes high cost and large waste; by adopting the conventional grouting material, if the goaf is filled, the slurry is difficult to quickly accumulate, the slurry loss is large, the calculus rate is low, and the treatment cost is greatly increased.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a collecting space area filling structure to solve among the prior art the great or tunnel of cavity and fill the collecting space area of water and when filling, the technical problem that the thick liquid loss is big, the calculus rate is low.

In order to achieve the above purpose, the technical scheme of the utility model is realized like this:

the utility model provides a collecting space area filling structure, include the tunnel obturator and end the thick liquid dam body, end the thick liquid dam body and extend along the direction of depth in collecting space area, end the thick liquid dam body set up in the week side of tunnel obturator is in order to form the curtain, end the thick liquid dam body and pour into by the concrete and form.

Further, the range of the repose angle of the grout stopping dam body is 30-35 degrees.

Further, the grout stopping dam body is formed by pouring concrete into a plurality of first grouting holes arranged on the boundary of the renovation range of the goaf, and the plurality of first grouting holes are arranged in rows at intervals; the maximum height of the grout stopping dam body is H, the center distance between adjacent first grouting holes in the same row is L1, and L1 is smaller than 3.2H; and/or the first grouting holes are arranged in multiple rows, the row spacing of the first grouting holes in adjacent rows is L2, and L2 is smaller than 3.2H.

Furthermore, the first grouting holes are arranged in multiple rows, and the first grouting holes in adjacent rows are arranged at intervals in a staggered mode.

Furthermore, the roadway filling body is formed by sequentially filling sand stones and slurry, and the slurry is filled between the sand stones.

Further, the slurry comprises the following components in a mass ratio of 0.8-1: 1.

Further, after the sand in the roadway filling body is filled, the range of the repose angle is 38-44 degrees.

Furthermore, the roadway filling body is formed by sequentially filling sand and slurry into a plurality of second grouting holes arranged in the renovation range of the goaf, the center distance between every two adjacent second grouting holes is L3, the stacking height of the sand is h, and then L3 is smaller than 1.95 h.

The utility model provides a goaf filling structure sets up the dam body that ends thick liquid along the depth direction in goaf, and ends thick liquid dam body and set up in the week side of tunnel obturator and form the curtain, play the effect of totally enclosed, can prevent to form the process of tunnel obturator and fill the bulk loss of material; the grout stopping dam body is formed by pouring concrete, a grout stopping curtain can be formed more effectively, and the problem of high difficulty in goaf treatment is solved.

Drawings

Fig. 1 is a schematic view of a transverse cross-sectional structure of a goaf filling structure provided in an embodiment of the present invention;

fig. 2 is a schematic longitudinal cross-sectional structural view of a goaf filling structure provided in an embodiment of the present invention;

FIG. 3 is a schematic plan view of the grout stopping dam shown in FIG. 1;

FIG. 4 is a cross-sectional view A-A shown in FIG. 3;

FIG. 5 is a cross-sectional view B-B shown in FIG. 3;

fig. 6 is a process flow diagram of the roadway packing construction of fig. 1.

Description of reference numerals:

10. a grout stopping dam body; 11. a first grouting hole; 20. a roadway filling body; 21. a second grouting hole; 30. a monitoring hole; 40. and (5) laneways.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. The descriptions of "first," "second," etc. in the present application are for descriptive purposes only and are not to be construed as indicating or implying any relative importance or implicit indication of the number or order of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

Referring to fig. 1 and 2, an embodiment of the present application provides a goaf filling structure, including a roadway filling body 20 and a grout stopping dam body 10, where the grout stopping dam body 10 extends along a depth direction of the goaf, the grout stopping dam body 10 is disposed on a peripheral side of the roadway filling body 20 to form a curtain wall, and the grout stopping dam body 10 is formed by pouring concrete.

Under the condition that the cavity of the goaf is large or the roadway 40 is filled with water, a large amount of slurry of the filling material easily flows out, the rapid accumulation is difficult, the calculus rate is low, and the treatment is difficult. In the embodiment of the application, the grout stopping dam 10 is arranged on the periphery of the roadway 40 in the goaf, the grout stopping dam 10 is arranged along the depth direction of the goaf, referring to fig. 1 and 2, the roadway 40 is completely sealed, and the roadway filling body 20 is prevented from losing a large amount of filling materials in the forming process. Fig. 1 shows only the grout stopping dams 10 on two opposite sides of the roadway 40, and the grout stopping dams 10 on the other two sides are not shown in the figure. The grout stopping dam body 10 is formed by pouring concrete, a grout stopping curtain can be formed more effectively, and the problem of high difficulty in managing the goaf is solved. Specifically, the repose angle of the grout stopping dam body 10 ranges from 30 degrees to 35 degrees.

In some embodiments, the grout stopping dam 10 is formed by pouring concrete into a plurality of first grouting holes 11 provided at the boundary of the renovation range of the goaf, and the plurality of first grouting holes 11 are arranged in rows at intervals. Referring to fig. 3 to 5, the maximum height of the grout stopping dam 10 is H, the center-to-center distance between adjacent first grouting holes 11 in the same row is L1, and L1 is less than 3.2H. The plurality of first injection holes 11 may also be arranged in a plurality of rows, and the row spacing of the adjacent rows of first injection holes 11 is L2, and L2 is less than 3.2H.

In the embodiment of the application, the first grouting holes 11 are used for pouring concrete into the goaf to form the grout stop dam 10, and the first grouting holes 11 are arranged on the boundary of the renovation range of the goaf, so that the grout stop dam 10 is formed on the periphery of the roadway 40 of the goaf and used as a curtain wall to completely seal the roadway 40, and the roadway filling body 20 is prevented from losing a large amount of filling materials in the forming process.

It can be understood that the number of the first grouting holes 11 is plural, that is, the grout stopping dam 10 is composed of a plurality of conical dams, and when the adjacent conical dams are overlapped and connected together, the blocking and sealing effect of the grout stopping dam 10 is best. Referring to fig. 3 to 5, assuming that the maximum height of the stop-grouting dam 10 is H, a plurality of first grouting holes 11 may be arranged in a row, and when the center-to-center distance L1 between adjacent first grouting holes 11 in the same row is smaller than 3.2H, the adjacent conical dams may be overlapped and connected; the plurality of first grouting holes 11 can also be arranged in multiple rows, and besides the condition that L1 is smaller than 3.2H is met, the row spacing L2 of adjacent rows is also smaller than 3.2H, so that adjacent conical dams in the same row or different rows are overlapped and connected, and the blocking and sealing effects of the formed grout stopping dam 10 are enhanced.

Specifically, for a larger gob, the hole pitch (i.e., L1) of the adjacent first grouting holes 11 in the same row is generally set to 5m to 8m, and the row pitch (i.e., L2) of the adjacent row is generally set to 3 m. And further, the first grouting holes 11 of adjacent rows are alternately arranged, referring to fig. 3. The adjacent rows of the first grouting holes 11 which are arranged at intervals in a staggered mode can enable the two rows of the formed grout stopping dam bodies 10 to be arranged in a staggered mode, and therefore the blocking and sealing effect of the grout stopping dam bodies 10 is enhanced. For a small goaf, the single-row first grouting holes 11 are designed as much as possible, and the hole spacing L1 between adjacent first grouting holes 11 is reduced to save cost.

In some embodiments, the roadway filler 20 is made of sand and slurry poured in series, with the slurry being filled between the sand and the slurry. In an environment where the goaf roadway 40 is filled with water, the filler material is easily diluted and isolated by water, which can result in a more easily lost filler material and a lower calculus rate. In the embodiment of the application, sand and stone are poured into the roadway 40 of the goaf before the slurry is poured, so that on one hand, a large amount of loss of subsequent slurry in pouring can be further prevented, and the slurry stopping effect is achieved; on the other hand, the sandstone can extrude out the water in the goaf, so that the subsequent slurry pouring is prevented from being diluted and separated by a large amount of water; finally, the sandstone and the slurry can form a double-layer structure, so that the flowability of the filling material is reduced, the loss of the roadway filling body 20 is avoided, and the filling quality and the goaf remediation effect are ensured.

Further, the slurry comprises the following components in a mass ratio of 0.8-1: 1. In the embodiment of the application, the slurry adopts cement fly ash grouting slurry, and a series of physical and chemical reactions between cement and fly ash are utilized to form the roadway filling body 20 with certain strength, water stability and integrity, so that the goaf filling structure is more stable. In addition, a large amount of fly ash is added into the cement, so that the cement consumption is saved and the engineering cost is reduced on the premise of meeting the grouting filling process requirement and the filling quality requirement. The slurry in the embodiment of the application can meet corresponding requirements in the aspects of pourability, calculus rate, compressive strength and the like.

In some embodiments, the roadway filling body 20 is formed by sequentially filling sand and slurry through a plurality of second grouting holes 21 arranged in the renovation range of the goaf, the center distance between adjacent second grouting holes 21 is L3, the stacking height of sand is h, and then L3 is less than 1.95 h. L3 is less than 1.95h for optimum hole spacing with simultaneous consideration of reduced drilling and filler material injection costs. In other embodiments, the angle of repose of the roadway filler 20 after completion of the sand fill is in the range of 38 ° to 44 °. The number of the second grouting holes 21 is multiple, and sand piles are formed when sand is poured into each second grouting hole 21; after the step of filling the sand and stone is finished, the repose angle is in the range, so that sand piles can be completely connected, and the filling effect is optimal.

The goaf treatment method comprises the following steps: s1, pouring concrete into the boundary of the renovation range of the goaf along the depth direction of the goaf, and forming a grout stopping dam body 10 on the peripheral side of the roadway 40 of the goaf; and S2, filling materials into the roadway 40 of the goaf to form the roadway filling body 20.

In the embodiment of the application, the grout stopping dam 10 is formed on the periphery of the roadway 40 in the goaf, the grout stopping dam 10 is arranged along the depth direction of the goaf, the roadway 40 is completely sealed, and the roadway filling body 20 is prevented from losing a large amount of filling materials in the forming process. The grout stopping dam body 10 is formed by pouring concrete, a grout stopping curtain can be formed more effectively, and the problem of high difficulty in managing the goaf is solved.

In some embodiments, step S1 is specifically: forming a plurality of first grouting holes 11 arranged in rows at intervals on the boundary of the renovation range of the goaf; concrete is poured into the first grouting holes 11 to form the grout stopping dams 10 on the peripheral sides of the lanes 40 of the goaf. Referring to fig. 3 to 5, the maximum height of the grout stopping dam 10 is H, the center-to-center distance between adjacent first grouting holes 11 in the same row is L1, and L1 is less than 3.2H. The plurality of first injection holes 11 are arranged in a plurality of rows, the row spacing of the adjacent rows of first injection holes 11 is L2, and L2 is less than 3.2H.

And after the effective concrete grout stopping dam body 10 is formed at the boundary of the renovation range of the goaf, filling the roadway 40 in the middle of the goaf. In some embodiments, step S2 is specifically: forming a plurality of second grouting holes 21 in the renovation range of the goaf, wherein the plurality of second grouting holes 21 are arranged at intervals, and refer to fig. 1; the second grout holes 21 are filled with gravel and then with grout to form the tunnel fillers 20 in the tunnels 40 of the gob.

In an environment where the goaf roadway 40 is filled with water, the filler material is easily diluted and isolated by water, which can result in a more easily lost filler material and a lower calculus rate. In the embodiment of the application, sand and stone are poured into the roadway 40 of the goaf before the slurry is poured, so that on one hand, a large amount of loss of subsequent slurry in pouring can be further prevented, and the slurry stopping effect is achieved; on the other hand, the sandstone can extrude out the water in the goaf, so that the subsequent slurry pouring is prevented from being diluted and separated by a large amount of water; finally, the sandstone and the slurry can form a double-layer structure, so that the flowability of the filling material is reduced, the loss of the roadway filling body 20 is avoided, and the filling quality and the goaf remediation effect are ensured.

Specifically, the device for filling sand and stone into the second grouting hole 21 comprises a steel pipe frame, a material containing hopper, a square funnel, a standby tripod and an electric hoist. The sand filled in the embodiment of the application is medium-coarse sand with gravel. The material containing hopper is fixed by a steel pipe frame and is required to be stably and firmly arranged on one side of the second grouting hole 21; the specification of the square funnel can adopt 40cm by 40cm, and can also be adjusted according to the amount of the sand poured on site. Referring to fig. 6, the process flow of the construction process for filling sand into the second grouting holes 21 is as follows: determining a second grouting hole 21 needing to be poured firstly, installing a material containing hopper and a square funnel above the orifice of the second grouting hole, wherein the inlet of the square funnel is opposite to the outlet of the material containing hopper; during the pouring construction, the sand and stone are shoveled into the material containing hopper by using the loader, the gate of the material containing hopper is opened to let the sand and stone leak into the square funnel, and then the sand and stone are poured into the second grouting hole 21. In order to avoid blocking the second grouting holes 21 by large sundries, a steel bar screen is placed at the inlet of the square funnel, and the grid of the steel bar screen is not more than 5 cm. And after the filling, moving to the next second grouting hole 21 for grouting until the grouting is finished.

In some embodiments, in the step of injecting sand and then injecting slurry into the second injecting hole 21 to form the roadway filler 20 in the roadway 40 of the gob, the angle of repose of the step of injecting sand is in the range of 38 ° to 44 ° after completion. The number of the second grouting holes 21 is multiple, and sand piles are formed when sand is poured into each second grouting hole 21; after the step of filling the sand and stone is finished, the repose angle is in the range, so that sand piles can be completely connected, and the filling effect is optimal. In other embodiments, the centers of adjacent second grouting holes 21 are spaced apart by L3, and the stacking height of sand is h, so that L3 is less than 1.95 h. L3 is less than 1.95h for optimum hole spacing with simultaneous consideration of reduced drilling and filler material injection costs.

Further, in the step of filling the second grout hole 21 with sand and then with slurry to form the roadway filler 20 in the roadway 40 of the gob, sand and stone are filled by a water-flush method. Specifically, the fine water flow is used for scouring the gravels at the gate of the material containing hopper, so that the flowing speed of the gravels can be improved, the friction between the gravels and the hole wall of the second grouting hole 21 is reduced, and the gravels poured into the roadway 40 are more compact. Directly provide the filling material for second slip casting hole 21 through setting up flourishing hopper and square funnel at the scene to adopt the water-washed method to accelerate the speed of pouring of grit, can effectively improve the efficiency of pouring the grit, guarantee the efficiency of construction. If the goaf is positioned near the existing road or railway, the second grouting holes 21 close to one side of the existing road or railway are constructed firstly when the gravels are poured, and then other second grouting holes 21 are sequentially poured along the direction towards the grout stopping dam body 10. In order to improve the pouring efficiency, the measures of simultaneous construction of the adjacent second grouting holes 21 are taken on site. The filling rhythm should be mastered in the process of filling the gravels, a channel is reserved for filling the gravels in the later period, the single-hole filling amount is estimated in advance, and the second grouting holes 21 are prevented from being blocked.

In some embodiments, step S2 further includes: before the step of filling the second grouting holes 21 with the gravels, a plurality of monitoring holes 30 are formed in the renovation range of the goaf, and settling pipes are placed in the monitoring holes 30 to monitor the compression deformation of the gravels by the slurry, the infiltration of the slurry and the water-separating shrinkage. It will be appreciated that the monitor holes 30 are not coincident with the second grout holes 21 and are spaced apart. After the slurry is poured into the second grouting hole 21, a sand layer at the lower part of the slurry generates obvious compression deformation; in addition, during and after completion of the slurry pouring, there are cases where the slurry seeps and shrinks due to water. In the renovation scope of the goaf, namely in the corresponding position of the roadway 40 of the goaf, the monitoring hole 30 is arranged, and a sedimentation pipe is arranged in the monitoring hole 30, so that the above various conditions can be monitored. When the above conditions are serious, after the step of pouring the gravel and the slurry is completed, the slurry needs to be refilled and poured once in each second grouting hole 21, so that the filling quality and the roof contact rate are ensured.

In the embodiment of the present application, after the sand is poured into the second grouting hole 21 and the condition of the dam body 10 and the sand is verified, the grouting is started into the second grouting hole 21. The slurry comprises the following components of cement, fly ash and water, namely the cement fly ash slurry is adopted. In the embodiment of the application, the mass ratio of the cement to the fly ash to the water in the slurry is 0.8-1: 1. Specifically, the device for pouring the grout into the second grouting hole 21 comprises a stirring barrel, a grout storage tank, a grouting machine, a pressure pump, a standby tripod and an electric hoist, and the grout can be poured by adopting methods such as self-flow grouting, pressure grouting, intermittent grouting and the like respectively or comprehensively according to actual conditions on site. In some embodiments, when the grout is poured into the second grouting holes 21 close to the grout stopping dam body 10, an accelerator is added into the grout, and the grouting is performed by using an intermittent grouting method. In order to better block the grout stopping dam, the intermittent grouting effect adopted by the second grouting holes 21 close to the grout stopping dam body 10 is better; when grouting is carried out in the row of second grouting holes 21 close to the grout stopping dam body 10, a proper amount of accelerating agent is added into the grout, so that the top gap of the grout stopping dam body 10 can be blocked.

In addition, if the gob is located near the existing road or railway, when grout is injected into the second grouting holes 21, the second grouting holes 21 adjacent to the existing road or railway are constructed first, and then the other second grouting holes 21 are sequentially injected in the direction toward the grout stopping dam 10. Due to the factors of slurry drainage shrinkage, penetration to a sand layer and the like, gaps are generated at the top after slurry is poured, and the filling quality of the goaf is affected. After the step of grouting slurry is finished, the drilling machine is used for sweeping holes of all the second grouting holes 21, residual cement slurry in the holes is removed, the depth of the holes is 1-2 m when sand and stone enter the holes, and then the slurry is pressure-grouted again. The slurry can be supplemented by pure cement slurry with the water cement ratio of 1: 1, and the grouting pressure is 0.5 MPa-2 MPa. The requirements for stopping grouting, which each second grouting hole 21 should satisfy, are as follows: (1) the normal grouting pressure is 0.6 MPa-0.9 MPa, and if the pressure indication of the pressure gauge exceeds the pressure value and continuously rises, the grouting can be stopped when the pressure indication reaches 1.5 MPa; (2) grouting flow is less than 10L/min within 20 minutes; (3) grouting may be terminated when slurry emerges from the surface of the adjacent hole. And stopping grouting when one of the three conditions is met.

The embodiment of the application provides a gob renovation structure which is characterized in that a grout stopping dam body 10 is arranged on the periphery of a roadway 40 in a gob to form a curtain wall, and then sandstone and grout are filled in the roadway 40 to form a roadway filling body 20. The goaf treatment method comprises the following specific implementation processes:

(1) preparing for construction and pouring concrete to form a grout stopping dam body 10: the preparation work of concrete, filling materials and equipment is included; then, pouring of the concrete grout stopping dam body 10 is carried out, and the pouring completion condition of the grout stopping dam body 10 is verified.

(2) And (3) gap plugging treatment of the concrete grout stopping dam body 10: in order to form a complete closed space in the goaf, the cement fly ash slurry is added with an accelerating agent to plug the gap of the grout-stopping dam body 10 before the sand and the slurry are poured.

(3) Arranging monitoring holes 30: before sand is poured, a monitoring hole 30 is arranged in the middle of the second grouting hole 21, the mounted settling pipe is placed into the monitoring hole 30, and a protective measure is taken at the opening.

(4) Filling sand and stone: referring to the process flow of fig. 6, the hole needing to be filled firstly → the loading hopper with the mounting hole → the square hopper with the mounting hole → the loading machine for loading → the filling by opening the valve → the filling is completed and then the next hole is filled → the sand filling is completed.

(5) Filling grouting liquid: the process flow refers to fig. 6, the completion of the grout stopping dam body 10 and the grouting of the sandstone is verified → the casing pipe in the hole for installing and fixing the second grouting hole 21 → the cement fly ash slurry is prepared → the grouting equipment is installed → the grouting slurry → the hole cleaning and the slurry supplementing → the hole sealing.

(6) And (3) analyzing a monitoring result: and analyzing the filling effect according to the monitoring data of the monitoring hole 30. If the compression deformation of the lower sand stone layer obviously exists in the slurry pouring process or the slurry infiltration and serious water separation shrinkage exist after the slurry pouring is finished, the second grouting holes 21 are subjected to one-time grouting after the slurry pouring is finished, and the filling quality and the roof contact rate are ensured.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the scope of the present invention. Moreover, the technical solutions of the present invention between the various embodiments can be combined with each other, but it is necessary to be able to be realized by a person having ordinary skill in the art as a basis, and when the technical solutions are combined and contradictory or cannot be realized, it should be considered that the combination of the technical solutions does not exist, and the present invention is not within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A goaf filling structure is characterized in that: including the tunnel obturator and end the thick liquid dam body, end the thick liquid dam body and extend along the depth direction in collecting space area, end the thick liquid dam body set up in the week side of tunnel obturator is in order to form the curtain, end the thick liquid dam body and pour into by the concrete and form.

2. A gob filling structure according to claim 1, wherein the angle of repose of the grout stopping dam ranges from 30 ° to 35 °.

3. The gob filling structure according to claim 1, wherein the grout stopping dam is formed by pouring concrete through a plurality of first grouting holes provided at a boundary of an remedial range of the gob, the plurality of first grouting holes being provided at intervals in a row;

the maximum height of the grout stopping dam body is H, the center distance between adjacent first grouting holes in the same row is L1, and L1 is smaller than 3.2H; and/or the first grouting holes are arranged in multiple rows, the row spacing of the first grouting holes in adjacent rows is L2, and L2 is smaller than 3.2H.

4. The gob filling structure of claim 3 wherein said first grout holes are arranged in a plurality of rows, said first grout holes of adjacent rows being alternately spaced.

5. The gob filling structure according to claim 1, wherein the roadway filler is poured with sand and slurry successively, the slurry being filled between the sand and the slurry.

6. The goaf filling structure according to claim 5, wherein the slurry comprises the following components by mass ratio, and the ratio of cement to fly ash to water is 0.8-1: 1.

7. The gob filling structure according to claim 5, wherein the lane filler is formed by sequentially injecting gravel and slurry through a plurality of second injection holes provided within the remedial range of the gob, a center-to-center distance between adjacent second injection holes is L3, and L3 is less than 1.95h when a stacking height of the gravel is h.

8. A gob filling structure according to claim 5, wherein an angle of repose of the gravel pack after completion of the gravel pack in the gallery filler is in the range of 38 ° to 44 °.