Method of excavating shallow tunnel in unstable soils
By using polyethylene pipes and semi-roof beams to stabilize the soil, the method addresses labor and material inefficiencies in tunneling through unstable soils, enhancing efficiency and reducing costs.
Patent Information
- Authority / Receiving Office
- RU · RU
- Patent Type
- Patents
- Current Assignee / Owner
- РЕМИЗОВ АЛЕКСЕЙ ВАЛЕРИЕВИЧ
- Filing Date
- 2026-03-01
- Publication Date
- 2026-07-01
AI Technical Summary
Existing tunnel construction methods in unstable soils face high labor intensity, metal consumption, and reduced tunneling speed due to drilling boreholes, pushing steel pipes, and installing protective screens and linings, leading to increased costs and prolonged commissioning times.
The method involves installing preliminary polyethylene pipes with conical tips using hydraulic jacks along the tunnel's longitudinal axis before excavation, dividing the tunnel into two halves vertically, and constructing semi-roof beams to form a protective shield, ensuring soil adhesion and stability during tunneling.
This approach enhances soil density and adhesion, reducing inelastic deformations and maintaining soil mass stability, thereby increasing tunneling efficiency and reducing labor and material costs.
Smart Images
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Abstract
Description
[0001] The invention relates to tunnel construction and can be used in the excavation of shallow tunnels in unstable soils to relieve the transport system and ensure free passage, for example, in the form of multi-level interchanges and underground pedestrian crossings, tunnels under intersections and railway crossings.
[0002] A method is known for installing protective screens made of pipes when driving deep tunnels in unstable soils [Tunnel Engineer's Handbook. Moscow: Transport. 1993, p. 309-312], in which inclined boreholes (at an angle of 4-6 degrees to the axis of the working) are drilled directly from the face into the ceiling of the working and steel pipes are pushed into them, while the screens are installed in sections of 10-15 m or more, overlapping adjacent sections by 1.5-2 m, and the tunnel is driven under the protection of the pipe screen in 2-3 m increments, reinforcing the screen with protective arches, and then a lining is erected. The disadvantages of this method are: high labor intensity of drilling boreholes and pushing steel pipes into them, high metal consumption during the installation of protective screens and arches, a decrease in the speed of tunneling during drilling boreholes and pushing steel pipes into them.
[0003] A known tunnel boring method [Author's Certificate SU 271555 A1, May 26, 1970, Bulletin 18, IPC E21D 9 / 00] involves tunneling by successively pressing individual hollow, thin-walled lining sections into the ground using jacks. After each element is pressed in, the soil is removed from its cavity and filled with concrete or mortar. However, this known method is labor-intensive, requiring the pressing of the lining elements, the removal of soil from them, and the filling with concrete. Furthermore, the installation of the lining elements requires significant time, and the tunnel takes a long time to commission.
[0004] The closest to the invention in technical essence is the method of tunnel excavation [Author's Certificate SU 1016519 A1, 07.05.1983, Bulletin 17, IPC E21D 9 / 00], in which hollow shells are pressed directly from the trench perpendicular to the longitudinal axis of the tunnel, filled with concrete, the earth core is extracted and the tunnel is secured.
[0005] The disadvantages of this method are the high costs of tunnel excavation, including the cost of digging a trench parallel to the longitudinal axis of the tunnel for the entire length of the latter and the metal consumption, a significant amount of work on pressing pipes from the trench above the tunnel being constructed and pumping hardening plastic mortar into them under pressure, in addition, the simultaneous reinforcement of a section of the tunnel following the movement of the shield and the collapse of the soil by pumping mortar from the pipes above this section may be unrealistic in terms of construction technology.
[0006] The technical result of the invention is to increase the density and adhesion of the soil in the roof of the tunnel and to ensure that the soil massif is kept from collapsing above the tunnel being constructed.
[0007] The set task is achieved by the fact that in the proposed method of driving a shallow tunnel in unstable soils, including the installation of preliminary lining and excavation of soil by a tunnel boring machine under the protection of the lining, before the start of tunneling, a preliminary pit is made and hydraulic jacks are installed in it, which are used to press polyethylene pipes with conical tips into the contour of the roof of the planned tunnel along the entire length and parallel to the longitudinal axis of the tunnel, excavation of soil and lining are carried out in stages with dividing the face into two halves vertically, after excavation of the first half, the first semi-upper casing made of a special profile is erected close to the polyethylene pipes perpendicular to the axis of the tunnel and supported on the side of the working with a metal stand, and in the center of the working with a temporary metal stand, after excavation of the second half, the second semi-upper casing is erected,It is connected to the first semi-roof using clamps and supported on the side of the excavation with a metal support. The excavation pattern and construction of the semi-roofs are then repeated. Once the tunnel is complete, the temporary metal support is removed. As the polyethylene pipes are pressed, the soil compacts and adheres to the pipe walls, and the two semi-roofs, firmly supported under the polyethylene pipes, form a protective shield in the tunnel roof, which maintains the soil mass above the tunnel being constructed.
[0008] A distinctive feature of the invention is that preliminary support made of polyethylene pipes is pressed into the contour of the roof of the planned tunnel before the start of tunneling operations along the entire length and parallel to the longitudinal axis of the tunnel, which increases the density of the soil and its adhesion to the polyethylene pipes in the roof of the tunnel, and the excavation of the soil and the support of the tunnel are carried out in stages in two halves vertically, which reduces the development of a zone of inelastic deformations in the contour of the workings.
[0009] The essence of the proposed method is explained by the following description and the drawings provided for it.
[0010] Fig. 1 shows a sectional diagram of pressing polyethylene pipes from a preliminary pit; Fig. 2 is a cross-section A-A in Fig. 1; Fig. 3 is a diagram of soil excavation and construction of semi-roofs from a special profile, view from above; Fig. 4 is a cross-section B-B in Fig. 3.
[0011] The diagrams show: 1 – preliminary pit; 2 – hydraulic jack for pressing in polyethylene pipes; 3 – polyethylene pipes with conical tips; 4 – tunnel; 5 – first half; 6 – second half; 7 – first half-upper beam made of special profile; 8 – metal racks; 9 – second half-upper beam made of special profile; 10 – tension clamps.
[0012] The proposed method is carried out as follows. After excavating a preliminary pit 1 and installing hydraulic jacks 2 in it, polyethylene pipes 3 (e.g., standard pipes with a diameter of 150-200 mm) with conical tips are pressed into the roof contour of the planned excavation and parallel to the longitudinal axis of the tunnel. The distance between the pipes is determined by the physical and mechanical properties of the soil. The pipes are pressed using hydraulic jacks 2 along the entire length of tunnel 4.After the preliminary support of polyethylene pipes 3 is installed, the excavation is carried out in stages using a tunnel boring machine, dividing the tunnel into two halves vertically 5-6. Following the excavation of the first half 5, the first semi-roof beam 7 made of special profile is erected close to the polyethylene pipes 3 perpendicular to the tunnel axis 4 and supported by metal supports 8. Following the excavation of the second half 6, the second semi-roof beam 9 is erected and connected to the first semi-roof beam 7 using tie clamps 10. The excavation pattern and the erection of semi-roof beams are then repeated. Upon completion of the tunnel construction, the temporary metal support 8 is cut off. Polyethylene pipes 3 embedded in the roof of the workings and semi-roofs made of special profile 7, 9 installed perpendicular to them form a protective shield that ensures the stability of the soil mass above the tunnel 4 being constructed.
Claims
A method for driving a shallow tunnel in unstable soils, including the installation of preliminary lining and excavation of soil by a tunnel boring machine under the protection of the lining, characterized in that before the start of tunnel boring, a preliminary pit is made and hydraulic jacks are installed in it, preliminary lining is arranged in the contour of the roof of the planned tunnel parallel to the longitudinal axis of the tunnel, pressing polyethylene pipes with conical tips with hydraulic jacks along the entire length of the tunnel, excavation of soil is carried out in stages by passes that divide the tunnel into halves vertically, after excavation of the first half, the first semi-roof made of a special profile is erected close to the polyethylene pipes perpendicular to the axis of the tunnel and supported on the side of the working with a metal stand, and in the center of the working with a temporary metal stand, after excavation of the second half, the second semi-roof is erected,they connect it to the first half-upper beam using clamps and support it on the side of the workings with a metal stand, after which the pattern of excavation and construction of the half-upper beams is repeated.