RU2537711C1 - Erection of tunnels in structurally unstable soils with karst phenomena and/or boil processes - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: proposed method comprises erection of forepoling along shotwall contour. Wells of the first type are drilled along contour of shotwall with said soils, injectors are fitted in every said well to inject solidifying mortar to well bed so that first contour of forepoling is produced from at least one layer of solidifying elements and compacted soil there between. Said first-type wells are arranged so that, at injection, intersecting zones of compacted soil are formed between adjacent wells. Solidifying elements hardened, second-type wells are drilled around forepoling first contour. Solidifying mortar is injected to well walls to make, over the forepoling height, a protective massif of one or several lines of elements intersecting in horizontal. Then, third-type wells are made with their bottoms to be arranged in imaginary cylindrical or elliptic surface above forepoling zone and thereunder. Hear, solidifying mortar in injected into plies of soil located under third-type well bottoms to produce cylindrical or elliptic roof above forepoling zone and thereunder composed by one or more lies of flat-parallel elements intersecting in horizontal to make a geological massif. Soil above said roof plies is additionally compacted by drilling fourth-type wells to inject there through said solidifying mortar into natural cavities and fractures formed in geological massif formation. Mortar can be composed of stock mix containing siliceous component, gas-forming agent, liquid sodium glass and sodium oxide hydrate solution, or simple sand-cement mortar. Said mortar is injected in resilient shells prefilled in said first- and third-type wells in soils with boil processes and second-type wells in extreme lines from forepoling.

EFFECT: forepoling over shotwall contour, higher reliability of soil massif.

6 cl, 4 dwg

Description

The present invention relates to mining and underground construction, in particular to the field of tunneling, and can be used in the construction of subway tunnels, road and railway tunnels and underground workings in weakly stable soils and soils with karst phenomena and / or suffusion processes, as well as in flooded soils with water flows in the face zone.

Known methods for the construction of tunnels by the shield method, characterized by the use of a tunneling shield in the face of the tunnel, under the protection of which they perform the development and cleaning of the soil, securing the face and erecting the lining. When constructing tunnels in unstable soils, tunneling operations are preceded by work to protect the face from the release of soil, which could result in an emergency (collapse of the face, flooding of the tunnel, the formation of surface dips and the destruction of buildings). The development and fastening of the face depend on the nature and condition of unstable soils, their water cut. In irrigated soils, additional short diaphragms installed in the shield cells are used, which form a kind of hydraulic shutter in the support ring of the shield when water breaks into the face (1).

However, the well-known methods of shield tunneling do not solve the problems of subsequent protection of tunnels from processes occurring in weakly stable and flooded soils and soils with karst phenomena and suffusion processes, which can lead to collapse of the soil above and below the tunnel during its operation.

There is also a known method of constructing an underground mine during paneling using elements of a precast ring reinforced concrete, cast-iron or any other lining material, including excavating the soil with a mechanized shield, grouting the sealing space through openings in the elements of the precast circular lining with cement grout, while filling part of the sealing space on the length of 0.25-0.75 the length of the element of the prefabricated ring lining behind the first after the shield lining ring is cement slurry with a length With the maximum setting time, the next development stage, at a length of 0.5-1 the length of the prefabricated ring lining element, is carried out with a mixture of grouting mortar with the setting accelerator, and then at the stage of technological shutdown of the shield for mounting the next lining ring, the grouting pressure is the lining space behind the first lining ring after the shield is supported by filing grouting mortar with a long setting time into the area of the lining space section, initially with complements cement slurry with a long curing period. The known method of constructing an underground mine during paneling using elements of a prefabricated ring lining can most successfully be applied in difficult hydrogeological conditions for laying a tunnel, characterized in some areas by the presence of groundwater, as well as zones of tectonic fracture (2).

The use of grouting mortars of long-setting mixtures in heavily flooded soils and soils with suffusion processes can lead to their increased consumption due to leaching of the mixtures with groundwater. In addition, the known method does not solve the safety problems of underground mining.

The closest in purpose and technical nature to the claimed method is a method of constructing deep tunnels in weakly stable soils, including the construction of an advanced lining in the form of a slit cut along the contour of the face filled with concrete mortar, under its protection, installation of a permanent lining and development of the face rock, while the gap with the given parameters, they are cut into sectors, alternately on each side of the central pedigree pillar, on the one hand, from the arch heel line to the pillar, and on the other, from the pillar to the heel line with water, into the gap cut on both sides of the pillar from the side of the alkaline working body, the separation is established, and at the end of the gap - the end pneumatic formwork, the gap is filled with concrete solution, with the time interval necessary for the concrete to set, the gap is cut in the central rock pillar and filled with concrete with a solution, thus constructing the leading lining with the excess of the lining contour by the amount of the installation gap, under the protection of the previously constructed leading lining, a constant lining is mounted, then at intervals nor necessary to set the strength of concrete advanced again erected lining, the top of the face schelerezhuschego working body develop breed one stope, wherein the cutting slit and development rock face are schelerezhuschim body mounted before application to the face to a predetermined cutting angle (3).

The disadvantage of this method is the impossibility of further protection of the tunnels themselves and the surrounding soil masses from processes occurring in structurally unstable and flooded soils and soils with karst phenomena and suffusion processes. In addition, when cutting cracks in a known manner in soils with karst formations and suffusion processes, it is possible that the contour of cracks can get into karst voids, in soils weakened by suffusion processes, and the formation of lining using pneumatic formwork will require additional measures to strengthen the soil, which will lead to a sharp increase in the cost of construction .

The technical problem to be solved by the claimed method of constructing tunnels is the formation in structurally unstable soils with karst phenomena and suffusion processes of a geomass capable of holding the face and soils adjacent to the face contour from collapse.

The technical result when using the proposed method is the formation of leading lining along the contour of the face in structurally unstable soils and soils with karst phenomena and suffusion processes and increasing the reliability of the soil mass in which the tunnel is to be laid.

This result is ensured by the fact that in the method of constructing tunnels in structurally unstable soils with karst phenomena and suffusion processes, including the construction of leading lining along the contour of the face, according to the invention, along the contour of the face, including weakly stable soils with karst phenomena and / or suffusion processes, form wells the first type, in each of which injectors are injected and a hardening solution is injected at the base of the wells, forming around the bottomhole contour the first contour of the lining at least in one layer from solid elements and compacted soil between them, while the wells of the first type are positioned so that when injecting a hardening solution between adjacent wells, intersecting zones of compacted soil are formed, while the distance between neighboring wells is at least 2 m, then after building strength with solid elements around the first contour of the lining form wells of the second type, in which, through injectors, a hardening solution is injected into the walls of the wells, forming fences along the bottom of the hole a solid array of one or more rows of solid elements intersecting horizontally; then the third type of wells is performed, the lower bases of which are arranged on an imaginary cylindrical or ellipsoid surface above and below the bottom zone, into which, by means of injectors, a hardening solution is also injected into the soil layers located below the bases of the third type wells, forming a cylindrical above the bottom zone and under it or an ellipsoidal arch of one or more layers of plane-parallel solid elements intersecting horizontally with the formation of a geomass along the contour of the face, while an imaginary cylindrical any or ellipsoid surface above and below the bottom zone, on which the wells of the third type are located, extends beyond the zone covered by the wells of the second type, and the formation of cylindrical or ellipsoidal arches above the upper and lower bottom zones from the plane-parallel solid elements leads simultaneously in all directions from arch points with a maximum or minimum depth to the highest or lowest point of the arch, then further compact the soil above the indicated solid elements by performing four wells grated type and injection of the hardening mortar from top to bottom or from bottom to top into natural cracks and voids formed during the formation of the geomassive, using sand-cement mixtures and / or a raw mix containing a siliceous component, a gasifier, liquid sodium glass and a solution of sodium hydroxide, which in soils with suffusion processes in wells of the first and third type, as well as in wells of the second type in the extreme rows of the array being formed, is injected into flexible shells introduced into the wells at the same time, the hardening mixture is injected in wells of the first, second and fourth types in height in increments of 1 to 3 m, and fly ash with successive addition of lime to it is used as a siliceous component in the feed mixture fluff, a blowing agent and a stabilizer of the mixture in the form of wood sawdust, moreover, a surfactant-grade aluminum powder with a particle size of up to 100 microns and / or aluminum powder is used as a blowing agent.

The inventive method of constructing tunnels in structurally unstable soils with karst phenomena and suffusion processes is represented by a sequence of four types of wells designed for injecting a hardening solution into them to strengthen the soil masses adjacent to the face by forming an advanced support in the form of a geomass around the face contour, excluding the possibility of collapse of the face and adjacent soils. The formation of a leading lining around the face contour in the form of a geomass of solid elements and compacted, with zones intersecting in the vertical plane, the soil between them hardens unstable soils with karst processes, provides dehydration of waterlogged soils and soils adjacent to the bottom contour with suffusion processes, which increases reliability daily surface of the array. At the same time, the conditions for performing and placing wells and the conditions for injecting a hardening solution into them specified in the claimed method, in particular: the wells of the first type, in which the hardening solution is injected at the base of the well to form the first contour of the lining; wells of the second type, in which the hardening solution is injected into the walls of the wells - to form a barrier array along the bottom of the hole; wells of the third type, in which the hardening solution is injected into the soil below the base of the wells - to form arches on an imaginary cylindrical or ellipsoid surface above the bottom and below it; and wells of the fourth type, in which the hardening mortar is injected into the cracks and voids formed - to strengthen the soil above the upper arch, they provide the formation of the leading lining in the form of a geomass, which has increased reliability and ensures subsequent safety to objects located on the surface of the massif during construction under them tunnel and its further operation. Moreover, due to the use of a raw material mixture containing a siliceous component, a gasifier, liquid sodium glass and a solution of sodium hydroxide as a hardening solution instead of or in conjunction with traditional sand-cement solutions, the formation of aluminosilicate solid elements in the created geomass, which are characterized by a short set time strength and subsequently are not subject to destruction by suffusion flows; the reliability of the formed geomass is increased. In particular, the formation of solid elements from a raw material mixture with a siliceous component in flexible shells previously introduced into the wells of the first, third and in the extreme row of wells of the second type provides a design, guaranteed formation of leading support along the contour of the face in weakened soils with karst and / or suffusion processes , which reliably protects the contour of the face from collapse of the soil and the breakthrough of groundwater into the face, and the subsequent strengthening of the soil above the created lining will eliminate the possibility after uyuschih suffusion and karst phenomena in a fortified the array, and the consequent collapse of soil. Moreover, the use of flexible shells for the formation of solid elements provides the possibility of using traditional sand-cement mixtures and the stability of the parameters of the obtained solid elements and eliminates the erosion of the raw material mixture introduced into the soil.

An example of performing advanced lining along the contour of the face laid in soils with karst formations of the tunnel is illustrated by sketches.

Figure 1 shows a section of an array of soil with karst formations and suffusion flows with a contour of the face in it.

Figure 2 presents a cross section of the contour of the face with the wells of the first type to form the first contour of the leading lining in cross section.

Figure 3 presents the contour of the face with a guard array made along it.

Figure 4 shows a section of the contour of the face with the leading support in the form of a geomass.

The method of constructing tunnels in weakly stable soils and soils with karst phenomena and / or suffusion processes was carried out on the experimental site as follows.

As a result of the pre-design studies of the soil mass, in which the tunnel was supposed to be laid, a system of zones of increased fracture characteristic of soils with karst processes was revealed, and at the intersections of several cracks, collapse domes 1 were recorded at a depth of 8 to 18 m in aquiferous layers due to suffusion washout minerals of soil (Figure 1).

Given the size of the collapse 1 (more than 1 m), according to the requirements of SP 11-105-97, etc. t.5.1 soil mass has V stability category relative to the intensity of the formation of karst dips, i.e. they are potentially dangerous, therefore, the soil mass in which the face contour passes is subject to hardening.

On a strengthened experimental site, the territory of which was at least 1000 m ² , two rows of wells of the first type were formed along the bottom contour, located at a distance from each other in a row and between rows of at least 2 m into which injectors were introduced (in the drawings not shown) to form the first contour of the lining. Through injectors in the lower part of the wells, at the bases, the raw material mixture was pumped into flexible shells 3, in which the fly ash was used as a siliceous component with successive addition of lime-fluff, a blowing agent and a mixture stabilizer in the form of sawdust, and as a blowing agent used surfactant-grade aluminum powder with a particle size of up to 100 μm and / or aluminum powder, forming solid aluminosilicate elements 4.

When using the specified raw material mixture for the formation of solid elements in the specified sequence as a result of reaction with aqueous alkaline solutions of the selected blowing agent - aluminum powder with particle sizes from 50 to 100 microns, hydrogen gas is released, leading to rapid foaming of the reaction mass and for a short time period under the protection of flexible shells 3, aluminosilicate elements are formed, characterized by a short period of curing, insoluble in water even When breaking through flexible shells. In this case, the reaction of a raw material pumped into flexible shells containing a silica component with a blowing agent, which is used as aluminum powder, and with a liquid sodium glass and a solution of sodium hydroxide hardener, is accompanied by the release of a large amount of heat, which leads to boiling in the volume of flexible shells 3 water and a sharp increase in pressure, resulting in conditions for compaction of soils falling into the space between the formed aluminosilicate elements. The distances between the wells in the rows and between the adjacent rows of wells 1 of the first type were at least 2 meters, which was determined experimentally and is sufficient for the formation of vertically intersecting zones of compacted soil 5 formed around each of the solid elements 4.

At the end of the formation of the first contour of the lining from one row (or, if necessary, two rows) of solid aluminosilicate elements 4 and compacted soil 5 between them, the first row of wells 6 of the second type (Figure 2) were made, starting from the edge of the row from the bottom contour. Flexible shells 3 were preliminarily placed in these wells along the bottom height with a distance between them of at least 1 m (which was also experimentally determined) and the raw material mixture was pumped into them, forming a fence row of an array of solid aluminosilicate elements 7, around which zones of compacted soil 8 are created After a set of strengths by elements 7, a second, inner row of wells 9 of the second type was performed and the raw material mixture was injected into the walls of the wells, forming solid aluminosilicate elements 10 intersecting in horizontal on the on-line plane and vertically with solid aluminosilicate elements 7 of the wells 6. The zones of compacted soil 11 formed around the solid aluminosilicate elements 10 also intersect with the zones of compacted soil 8, forming an array impervious to groundwater.

Then, on the territory of the site above the face contour at a distance in rows and between rows of at least three meters, wells of the third type 12 were made (Fig. 3), placing their bases on an imaginary cylindrical or ellipsoid surface above the face zone, at a height that extends beyond the compacted soil zone 5 formed in the first contour of the lining, alternating the depth of the wells in rows so that their bases form two layers of an imaginary cylindrical or ellipsoid surface. Between the wells 12, wells of the third type 13 were located, the bases of which were also arranged in two layers along an imaginary cylindrical or ellipsoidal surface under the face contour below the area of compacted soil of the first support lining. The width of the area covered by the wells of the third type 12 and 13 was greater than the distance between the extreme rows of wells 6 of the enclosing array formed along the bottom contour. In the wells of the third type 12 and 13, by means of injectors, the raw material mixture was injected into the soil below the base of the wells, forming above the bottomhole contour and below it in two layers of vaults of solid elements intersecting in the horizontal plane 14. Formation of arches above the upper and lower bottomhole zones from plane-parallel solid Elements located on an imaginary cylindrical or ellipsoid surface were driven by a solution simultaneously in all wells of the third type in all directions from the arch point with a maximum depth to the bottom m arch or minimum depth of - in the upper arch to the highest or lowest point of the arch respectively. Moreover, in the upper arch above the bottomhole zone formed by the bases of the wells 12, and in the lower arch below the bottomhole zone formed by the bases of the wells 13, the raw mix was injected into flexible shells. After curing by the formed plane-parallel elements 14 and extraction of injectors from the wells, the bottomhole contour was passed using the shield method. Over the formed upper arch of solid elements 14, between which zones 15 of compacted soil were also formed, after gaining strength by plane-parallel elements 14 in the soil mass, wells of the fourth type were made over the bottom contour and, by injecting the raw material mixture into the walls of the wells, the existing and formed wells were filled during the formation of the support of cracks and voids formed by the solid elements 17 formed in them, creating a geomass of increased strength.

As a hardening mixture for the formation of the leading lining in the form of a geomass on a certain section of the face contour, a sand-cement mortar was also pumped into flexible shells. However, the use of sand-cement mortar required high energy costs for supplying the mortar to the injectors for the formation of solid elements and areas of compacted soil around the formed solid elements, and the latter gaining strength required more time, which lengthened the total formation time of the geomass. The use of the proposed raw material mixture containing silica components provided a number of advantages: the formation of aluminosilicate solid elements, accompanied by the release of water and its boiling, created a greater force on the soil around the formed solid elements without additional energy costs and reduced the time of formation of leading lining

Due to the formation of multi-layer leading lining around the face contour from solid aluminosilicate elements intersecting in the vertical and horizontal planes and zones of compacted soil between them, located around the face contour and hardening of the soil above the face contour, and due to the use of the proposed raw material mixture to strengthen the soil, a monolithic geomass is created, providing improving the reliability of structurally unstable soils and soils with karst phenomena and / or suffusion processes. At the same time, a significant economic effect is achieved due to the use of cheap raw materials for preparing the raw mix and the reduction in energy costs for introducing the raw mix through injectors into wells of various types and into the ground.

Information sources

1. Filippov I.I. Tunnels constructed by shield and special methods. Textbook, M .: RGOTUPS, 2004, p. 3, 176-179.

2. Description to the patent No. 2476675 according to the application No. 20111110274/03 of 03/18/2011 for the invention "Method for the construction of underground workings with shield tunneling", published 02.27.2013

3. Description to the patent of the Russian Federation No. 2096621 for the invention “A method for constructing deep tunnels in weakly stable soils” according to the application No. 96101124, published on November 20, 1997.

Claims (6)

1. The method of constructing tunnels in structurally unstable soils and soils with karst phenomena and / or suffusion processes, including the construction of leading lining along the contour of the bottom and characterized in that along the contour of the bottom, including these soils, form wells of the first type, in each of which injectors are injected and a hardening solution is injected at the base of the tales, forming around the face contour the first lining contour of at least one layer of hardening elements and compacted soil between them, while the wells of the first type and they are positioned so that when injecting a hardening solution between adjacent wells, intersecting zones of compacted soil are formed, then, after hardening by hardening elements around the first lining, form wells of the second type, in which hardening solution is injected into the walls of the wells by means of injectors, forming in height a slaughtering enclosure of one or more rows of horizontally intersecting elements; then the third type of wells is performed, the lower bases of which are arranged on an imaginary cylindrical or ellipsoid surface above and below the bottom zone, into which, by means of injectors, a hardening solution is also injected into the soil layers located below the bases of the third type wells, forming a cylindrical above the bottom zone and under it or an ellipsoidal arch of one or more layers of plane-parallel elements intersecting horizontally with each other with the formation of a geomass, after which the soil is further compacted above the aforementioned layers of the arch above the bottomhole zone by performing fourth type wells and injecting the hardening solution from top to bottom or from bottom to top in natural cracks and voids formed during the formation of the geomass, using sand-cement mortar and / or a raw material mixture as a hardening solution siliceous component, blowing agent, liquid sodium glass and a solution of sodium hydroxide, which in soils with suffusion processes in wells of the first and third types, as well as in boreholes second type zhinah in extreme rows of bottom injected into the previously entered into wells flexible sheath. 2. The method according to claim 1, characterized in that the wells of the first type are indented from each other in a row and each row from each other for at least 2 m 3. The method according to claim 1, characterized in that the imaginary cylindrical or ellipsoidal surface above the bottom zone and under it, on which the wells of the third type are located, extends beyond the zone covered by the wells of the second type. 4. The method according to claim 1, characterized in that the injection of the hardening mixture in the wells of the first, second and fourth types is carried out in height in increments of 1 to 3 m 5. The method according to claim 1, characterized in that as a siliceous component in the raw material mixture, fly ash is used with successive addition of lime-fluff, a blowing agent and a stabilizer of the mixture in the form of wood sawdust, and a surfactant-grade aluminum powder is used as a blowing agent with a particle size of up to 100 microns and / or aluminum powder. 6. The method according to claim 1, characterized in that the formation of cylindrical or ellipsoidal vaults above the upper and under the bottom zone of the bottom of the plane-parallel elements are simultaneously in all directions from the point of the arch with maximum or minimum depth to the highest or lowest point of the arch.

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