RU2138643C1 - Method and device for construction of tunnel in loose ground - Google Patents

Abstract

FIELD: mining industry and construction engineering. SUBSTANCE: method and device are intended for driving tunnels and sewers in loose, unstable ground. Method includes operations of extracting rock matter and stabilizing loose ground around tunnel by injecting stabilizing solution into ground. Prior to extracting rock matter, pipes are driven into rock mass ahead of work face at angle to longitudinal axis of tunnel. Pipes are driven over contour of work face in picket fence manner that is one pipe close to another pipe with displacement along tunnel of subsequent picket fence relative to preceding picket fence by length L. Pipes are driven to length with its projection to longitudinal axis of tunnel exceeding length of its section L, thus creating herringbone pattern of pipes along tunnel. Device for construction of tunnel in loose ground has longitudinal member in the form of solution delivery pipe which is connected with pump supplying stabilizing solution. Tapered head-piece is mounted in front part of solution delivery pipe. Also provided is striking unit rigidly connected with pipe. Perforations are made in side wall of solution delivery pipe. Distance between these perforations corresponds to maximal radial size of sphere-like zone of stabilized loose ground. Aforesaid method and embodiment of device allow for construction of tunnel or sewer in weak, loose, and unstable ground. EFFECT: higher efficiency. 10 cl, 10 dwg

Description

 The invention is intended for tunneling, collectors in loose, unstable rocks and can be used in mining and municipal construction.

 A known method of constructing a tunnel in flooded unstable soils by AS USSR N 559006, class E 21 D 9/00, including operations on preliminary drainage of the soil mass along the tunnel route and its subsequent sinking, while before tunneling, the tunnel is sealed on all sides, then compressed air is supplied to the upper part of the sealed soil mass and pumping out ground water from the lower parts of the array with continuous supply of compressed air.

 The disadvantage of this method is the high energy costs associated with a continuous supply of compressed air throughout the construction of the tunnel. In addition, the tunnel construction method under consideration has a limited scope, since does not create soil binding forces; moreover, when groundwater is pumped out, small particles of soil are washed out, which contributes to the creation of artificial caverns in the array that increase the instability of the array.

 A known method of hardening an unstable roof by chemical anchoring (see, for example, Butenko I.T., Kara V.V., Salnikov V.K., Pikhovich I.Ya. Chemical method of hardening rocks in the working faces of coal mines, Kiev, "Technique ", 1978, pp. 26-40), including drilling holes, installing anchor rods in the holes, weighed runs on the ends of the anchor rods protruding from the rock mass and injecting a chemical solution (feeding a polyurethane foam composition into the hole or installing one or two ampoules with fixing composition). When the anchor rod moves deep into the hole, the foaming composition is pushed out to the hole of the hole.

 The disadvantages of the considered method are: multi-operation process (first they drill, then install an anchor rod, etc.), each of the anchors acts independently, without interacting with neighboring ones, which reduces the effectiveness of fastening.

 The closest in technical essence and the achieved result is a method of constructing a tunnel of short length along a.s. USSR N 620524, cl. E 21 D 9/00, including the creation of a closed wall of metal pipes, the injection of mortar through metal pipes and subsequent excavation, while one of the ends of the metal pipes is monolithic, the injection of mortar is carried out after excavation and installation of formwork, and excavation is carried out in parallel with the advancement of formwork.

 The disadvantage of this method of constructing a tunnel is the collapse of the surrounding loose soil during tunneling - the most dangerous stage of the work. In addition, the creation of a closed wall of metal pipes, leading to a large consumption of the latter, does not provide reliable protection against collapse, since the rock located above the pipes has the ability to move and the accumulated kinetic energy of the rock is held by the pipes only at the end of the movement of its elements ( pieces of rock).

 A device for fixing rocks with hardening solutions according to A.S. USSR N 1129366, class E 21 D 11/00, containing perforated discharge tubes with jackets of open-porous material fixed to them, which are impregnated with a solution hardening accelerator. A disadvantage of the known device is the inability to extract metal pipes after the end of the solidification process of the solution. In addition, rock consolidation occurs locally near the walls of metal pipes, which reduces the reliability of fixing a large volume of soil mass.

 The closest in technical essence and the achieved result is driven support for as. USSR N 1696716, cl. E 21 B 11/00, including a guide frame, driven rods with guides, a pressure mechanism for driving rods and power elements, while a downhole mechanism is installed on each rod and is rigidly fixed with it, and the pressure mechanism is made in the form of a hammer with a clip, and the support is provided with lateral tightenings with guides, front and rear additional guide frames made in the form of upper and side beams, and the upper beams have grips rigidly attached to it to move the guide rods into them, and lateral - vertical hydraulic cylinders in the lower parts.

 A disadvantage of the known driving lining is the low efficiency of rock fastening, because it is held only by the lateral surface of the rods. In addition, the complexity of the design makes it difficult, and in some cases eliminates the work, especially in cramped conditions with small diameters of the collectors.

 The technical problem solved by the proposed method of constructing a tunnel in bulk rocks is to pre-fix the rock around the tunnel to ensure interaction between the fixed zones and at the same time increase the efficiency of the work by combining the penetration of a hole and installing an anchor rod in it.

 This is achieved due to the fact that in the method of constructing a tunnel in loose rocks, including excavation of the rock and fixing the loose rock around the tunnel by injecting a fixing solution into it, according to the invention, pipes are hammered into the massif in front of the face before the excavation of the rock angle to the longitudinal axis of the tunnel, while they are placed along the contour of the face with a “picket fence” (one pipe near the other) with an offset along the tunnel of the subsequent “picket fence” relative to the previous one by a length L, and the pipes are driven yut for a length, the projection of which onto the longitudinal axis of the tunnel exceeds the length of its section L, forming a herringbone from the pipes along the tunnel. The sequence of the proposed operations provides the possibility of tunneling in a loose unstable array.

 It is advisable to hammer the subsequent "picket fences" (rows) of pipes into the array with a displacement along the perimeter of the face relative to the previous pipe "pickets" hammered into the array. Such an operation allows more consolidation of the bulk mass around the tunnel.

 It is also advisable to use pipes with perforations along the length along which the fixing solution is supplied and injected into the bulk rock. This embodiment of the method allows the use of one structural element - metal pipes - to perform various functions: securing the array located around the perimeter of the tunnel, transporting a fixing solution along it, which after a certain time will contribute to the consolidation of the surrounding bulk array.

 In this case, it is advisable to inject the fixing solution into the array locally in the form of sphere-shaped zones, the centers of which are located at a distance L from each other. Such operations can reduce the energy costs of injecting the fixing solution and the consumption of the latter.

 It is advisable to form spherical fixed zones of loose rock adjacent along the length of the tunnel to form one above the other in a checkerboard pattern. This performance of operations contributes to the effect of consolidation of loose rock around the tunnel due to the interaction of neighboring sphere-shaped fixed zones while reducing the cost of the volume of spent fixing mass and energy during injection.

 It is also advisable to hammer the “palisades” of pipes adjacent to the length of the tunnel at a distance along the tunnel equal to the width of the sphere-shaped fixed zone of loose rock. This operation allows individual spherical fixed zones of loose rock to work together due to the friction forces arising between them in the case of movement of one of the zones relative to the other.

 It is also advisable to hammer the “palisades” of pipes adjacent to the length of the tunnel to various lengths, while the spherical fixed zones of loose rock formed during the clogging of short pipes should be placed between the adjacent spherical fixed zones of loose rock formed along the length of the tunnel formed when clogging long pipes. This operation allows you to increase the reliability of fixing loose mass around the tunnel, because adjacent sphere-shaped fixed zones of loose rock will impede the movement of other sphere-shaped fixed zones.

 The device provides an implementation of the tunneling method in loose rocks and soft soils and simplifies the design by combining the operations of making a hole in an array, installing an injection unit in it, which at the same time serves as an element for attaching the tunnel arch.

 This is achieved due to the fact that in the device for constructing a tunnel in loose rocks, containing a longitudinal element in the form of a mortar pipe connected to a pump supplying a fixing solution, a conical tip mounted in the front of the pipe, and an impact assembly rigidly connected to the pipe, according to the invention, perforations at a distance from each other corresponding to the maximum radial size of the sphere-shaped fixed zone of loose rock are made in the side wall of the mortar supply pipe. This embodiment of the design of the device provides an implementation of the method of constructing a tunnel in loose rocks, since the entire arch of the tunnel will be fixed.

 It is advisable to perform annular collars ahead of the perforations in the mortar tube. This design eliminates the ingress of soil particles into the perforation of the solvent-supply pipe, which increases the reliability of the device, and hence the reliability of fixing the soil mass in the perforation zone.

 It is also advisable to carry out the solution-feeding pipe with bushings placed on its outer surface with the possibility of axial movement, and at one of its extreme positions the bushings overlap the perforations of the solution-supply pipe, while the annular collars on the solution-supply pipe are located behind the perforations. This embodiment of the device design increases the reliability of its operation, because eliminates the ingress of soil particles into the perforation during the driving of the mortar pipe into the soil.

 The essence of the invention is illustrated by examples of specific performance and drawings, where in: FIG. 1 shows an operation for driving longitudinal elements into a soil mass; FIG. 2 is a view along arrow A in FIG. 1; FIG. 3 - operation for the location of the longitudinal elements in the form of a "herringbone"; FIG. 4 is a section BB in FIG. 3; FIG. 5 - operation for local injection of the fixing solution into the array with the formation of a sphere-shaped zone; FIG. 6 - operation of fixing the array with the formation of "herringbone" with sphere-shaped fixed zones; FIG. 7 - fixing of the massif, when the sphere-shaped fixed zones of it are placed along the clogged pipe; FIG. 8 - operation to fix the array with sphere-shaped fixed zones formed in a checkerboard pattern; FIG. 9 - a device for the construction of a tunnel in bulk rocks; FIG. 10 - a device with movable sleeves for the construction of a tunnel in loose rocks.

 The essence of the proposed method of constructing a tunnel in bulk rocks is to drive the longitudinal elements 1 (rods, pipes, etc.) into the array located in front of the face, at an angle to the longitudinal axis of the tunnel 2 (Fig. 1), while they are arranged along the contour face (Fig. 2), as a result, a "stockade" of longitudinal elements 1 is formed, which diverges into the array, while the closer to the face, the distance between the longitudinal elements 1 decreases. The next step with excavation is the section of the tunnel L (Fig. 3) and repeat the operation. A new "picket fence" of longitudinal elements 1 is placed under a preceding "picket fence" with some part of its length, and then goes into the array. In this case, it is advisable to hammer the subsequent "picket" (row) of longitudinal elements 1 into the array with a displacement around the circumference relative to the previous "picket" of longitudinal elements 1 driven into the array. When driving longitudinal elements 1 into the array, on the one hand, the array is compacted by volume, occupied by clogged longitudinal elements 1, and on the other hand, part of the soil mass is based on longitudinal elements 1, which serve as beams, and on the third, friction along the lateral surface of longitudinal elements 1 contributes to u stability of the array. All these factors improve with an increase in the number of clogged longitudinal elements 1 both along the contour of the face, and with an increase in the number of "stockade" clogged into the array of longitudinal elements 1 (with decreasing step L). It should be noted that if at the beginning of the process, when the first “picket fence” of the longitudinal elements 1 is hammered in the bottom, the fixed section is small in depth, then subsequently around the tunnel some kind of rows will be formed consisting of the “stockings” of clogged longitudinal elements 1. The depth of the last the soil can be different and depends on the soil conditions and the cross section of the element to be clogged 1. Thus, pipes with a diameter of 219 mm can be driven up to 40 m on the basis of practical experience, welding their ends as they become clogged. The angle of inclination of the driven longitudinal element 1 into the array is selected from the condition of the depth of the tunnel (collector) and the physical and mechanical properties of the array. In this case, it is possible to lay a larger number of clogged longitudinal elements 1 in the arch of the tunnel than in its lower part.

 As the longitudinal elements 1, pipes are usually used. In this case, in addition to reducing the metal consumption, they can be used to supply a fixing mortar (cement-based or special polymer-based). The pipe can be perforated over its entire length or have a number of holes (perforations) placed at a certain distance from each other. In the first case, when the fixing solution is injected, a fixing zone is formed around the entire length of the pipe hammered into the array. However, increased costs of the fixing solution will be observed. When using a pipe with holes (locally perforated sections) there will be lower costs of the fixing solution, however, a smaller volume of the array will be fixed. The choice of the optimal number of perforated sections in the clogged pipe will depend not only on the properties of the array, but also on the number of rows of pipes “hammered” into the array, the distances from each other to the rows and pipes in each row.

 In the case of using pipes as longitudinal elements 1, it is possible to carry out additional fixing of the array by supplying a fixing solution through the pipe. If the pipe does not have perforations, then the solution injected through the pipe end forms a fixed zone 3 of a spherical shape (Fig. 5, 6), and with subsequent penetration, a "herringbone" (Fig. 6, 7) with sphere-shaped fixed zones is formed 3. The distance L between pipes clogged into the array can correspond to the diameter of the sphere-shaped fixed zone 3, as shown in FIG. 6, either due to different pipe angles or different pipe driving lengths, it can change. In this case, the structure will work as an anchor fixed in a sphere-shaped zone.

 When using a pipe with perforated holes along the entire length, sphere-shaped fixed zones 3 are formed along the clogged pipe (Figs. 7, 8). If the distance between the clogged pipes along the tunnel 2 corresponds to the width of the sphere-shaped fixed zone, then the contours of the sphere-shaped fixed zones interact with each other.

 When using pipes (Fig. 9) with holes displaced relative to each other at a distance l (perforations in individual sections), it is possible to form several sphere-shaped fixed zones 3 in the array. They can be located at the same distance from the tunnel 2 along the length of the latter (Fig. 7) or each adjacent along the length of the tunnel 2 sphere-shaped fixed zone 3 can be placed between the previous fixed zones 3 (Fig. 8). In this case, the sphere-shaped fixed zones 3 of the breed will be staggered along the length of the tunnel 2 and they will all work as a unit. At the same time, the costs of the fixing solution will be reduced. In this case, it is possible to implement two device designs with different locations of perforations (Fig. 8) or, using one device design, drive it into different lengths.

 At the end of the operation of injecting the solution into the rock, you can remove the pipe from the array. For this, a shock pulse is applied to the pipe in the opposite direction. Until the solution has set, the pipe is easily removed from the array.

 A device for constructing a tunnel in bulk rocks consists of a shock assembly 4 (pneumatic punch - Fig. 9 or PUMA - annular pneumatic impact machine - Fig. 10) and a longitudinal element 1 in the form of a mortar pipe with perforations 5. The front end of the pipe can be open or with conical tip 6. In front of (Fig. 9) or behind (Fig. 10) perforations 5 of the pipe can be made annular collars 7. Mortar-feeding pipe can be equipped with movable bushings 8, placed on its outer surface with the possibility of axial movement, than in one of their extreme positions they overlap the perforations 5. The annular collars 7 can be located in front of the holes 5 (Fig. 9) when the movable sleeve 8 is not used, or behind them. In the latter case, the movable sleeve 8 is placed in front of the annular shoulder 7 (Fig. 10).

 The device operates as follows.

 Impact unit 4 (Fig. 9, 10) clog into the array a longitudinal element 1, for example a pipe. As the shock unit 4, widely known pneumatic punches can be used (for example, according to the AS of the USSR N 1421844, class E 21 В 7/20, BI N 33, 1988) or PUMs (according to the AS of the USSR NSS 678904, CL E 02 D 7/02). When using a pneumatic punch, the latter is attached to the pipe to be hammered into its rear end (there is a “bite” of the pipe end on the conical surface of the front of the pneumatic punch). When using PUMs having an annular shape, the pipe is passed into the annular hole of the PUMs and fixed to it along the lateral surface due to the collet connection fixed in the PUM.

 Pipes with an open end (Fig. 9) or closed (Fig. 10) can be used. In the latter case, there is a conical tip 6, which can be fixed in the pipe or freely mounted on it.

 When the pipe is driven into the soil mass, the fixing solution is not fed into it. If the pipe has an open front end, then the soil fills its internal cavity by about 2 diameters, after which a plug is formed. If a pipe with a closed end is clogged, the conical tip 6 extends the soil in a radial direction. An annular shoulder 7, in the case of performing it in front of the perforations, serves to form a gap between the soil and the clogged pipe. When using movable sleeves 8, the annular collars 7 serve as an abutment for the sleeves 8, and the front surface of the sleeve 8 forms a well of a larger diameter than the diameter of the clogged pipe. When driving the longitudinal element 1 in the form of a perforated pipe into the soil mass, the movable sleeve 8, due to the friction forces on the soil, occupies the extreme left position, closing the perforations 5 from the ingress of soil. When clogging the longitudinal element 1 in the form of a perforated pipe without a movable sleeve 8 (Fig. 9), this function is performed by annular collars 7, forming after themselves a gap between the clogged pipe and soil.

 After the pipe with the open end is clogged to the required depth, a fixing solution is supplied through its internal cavity under pressure. The solution extrudes the cork and enters the ground. If there are perforations 5 in the side wall of the pipe, then the fixing solution through them enters the surrounding array. The diameters of the perforations 5 can be different, for example, the closer to the front of the mortar pipe, the larger they can be. In this case, the pressure in the solution exiting the pipe will be leveled, which will provide approximately the same dimensions of the sphere-shaped fixed zones in the array. In another embodiment, for example, the opposite, when the diameters of the perforations are larger towards the rear of the pipe, the sphere-shaped fixed zones will have different sizes, decreasing towards the front of the clogged pipe. By varying the diameters of the perforations, it is possible to adjust the sizes of the sphere-shaped fixed zones of the 3 array.

 After the pipe is clogged into the ground, it is removed from the soil by the stroke length of the movable sleeve 8 by reversing the shock assembly 4 and applying a shock pulse in the opposite direction. Due to the forces of friction against the soil, the movable sleeve 8 will be held in place and the pipe will move back. As a result, the perforations 5 of the clogged pipe will open and when the fixing solution is supplied, it will freely flow out of the pipe into the gap between it and the ground. In this case, the conical tip 6 can also remain in place due to the friction forces, and the pipe moves back, forming a gap between its end and the conical tip 6. In this case, the fixing solution will be injected into the ground through the front end of the driven pipe. The movable sleeve 8 and the conical tip 6 protect the perforations 5 and the end of the pipe when driving it into the ground, which ensures the outflow of the fixing solution from the perforations during injection. You can use a fixed conical tip 6, but in this case, in the front of the pipe there are additional perforations 5 (Fig. 10).

 The pipes can be driven to the same depth, but at the same time it is advisable to have the perforations 5 adjacent to the pipes at different distances from the end (front or rear). It is possible to use pipes of the same design, but they must be driven into different depths. These two technologies for executing the pipe driving operation ensure the location of the fixed zones 3 in a checkerboard pattern, which will ensure their joint work (Fig. 8).

At the end of the operation of injecting the fixing solution into the rock, it is possible, by applying a shock pulse in the opposite direction, to remove pipes clogged into the rock. To do this, when using a pneumatic punch as a shock unit 4, reverse is used, and when using PUMAs as a shock unit 4, it is rotated 180 ^° and fixed to the pipe.

 The proposed method and device for the construction of a tunnel in loose rocks allows its penetration by hardening with a hardening solution of the surrounding loose rock.

Claims (10)

 1. A method of constructing a tunnel in loose rocks, including excavation of the rock and fixing the loose rock around the tunnel by injecting a fixing solution into it, characterized in that before the excavation of the rock into the array in front of the bottom, the pipes are driven at an angle to the longitudinal axis of the tunnel , while they are placed along the bottom contour with a “picket fence” (one pipe next to the other) with a shift along the tunnel of the subsequent “picket fence” relative to the previous one by a length L, and the pipes are driven to a length projected onto Dolni tunnel axis exceeds the length of its portion L, forming of pipes "herringbone" along the tunnel.  2. The method according to claim 1, characterized in that the subsequent "picket fences" (rows) of pipes are hammered into the array with a displacement along the perimeter of the face relative to the previous pipes "stacked" into the array.  3. The method according to claim 1 or 2, characterized in that use pipes with perforations along the length along which serves fixing solution and inject it into the bulk rock.  4. The method according to any one of claims 1 to 3, characterized in that the injection of the fixing solution into the array is carried out locally in the form of sphere-shaped zones, the centers of which are located at a distance L.  5. The method according to claim 4, characterized in that the spherical fixed zones of granular rock adjacent along the length of the tunnel form one above the other in a checkerboard pattern.  6. The method according to any one of claims 1 to 4, characterized in that the "palisades" of pipes adjacent to the length of the tunnel are hammered at a distance along the tunnel equal to the width of the sphere-shaped fixed zone of loose rock.  7. The method according to p. 4, characterized in that the "pipe picket" adjacent along the length of the tunnel is hammered to different lengths, while the sphere-shaped fixed zones of loose rock formed by driving short pipes are placed between the sphere-shaped fixed zones of loose rock adjacent to the length of the tunnel formed by driving long pipes.  8. A device for constructing a tunnel in bulk rocks, containing a longitudinal element in the form of a mortar pipe connected to a pump supplying a fixing solution, a conical tip mounted in the front of the pipe, and an impact assembly rigidly connected to the pipe, characterized in that in the side perforation at a distance from each other, corresponding to the maximum radial size of the sphere-shaped fixed zone of loose rock, is made to the wall of the mortar pipe.  9. The device according to claim 8, characterized in that annular collars are made in front of the perforations on the mortar-feeding pipe.  10. The device according to p. 8, characterized in that the mortar pipe is made with bushings placed on its outer surface with the possibility of axial movement, and in one of its extreme positions the bushings overlap the perforations of the mortar pipe, while the annular collars on the mortar pipe are located behind perforations.

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