HU187741B - Method for drifting round tunnels being under groundwater level, in nonstable variable grounds - Google Patents

Abstract

The tunnelling method is used to produce a circular section tunnel in soft and waterlogged ground. The tunnels may be used for underground railways of the "tube" type. A shield (1) is used which has a circular cutting edge defining the outer profile of the tunnel. There are radial support elements (6) which may be sprung. They support radial elements (8) which bear outwards against the surrounding soil. These elements are brought into play when the soil is waterlogged and unstable. In hard and stable rock the elements are retracted. Concrete is injected at the rear of the shield to make the tunnel lining.

Description

FIELD OF THE INVENTION The present invention relates to a method for constructing submerged tunnels under groundwater in non-volatile soils.

The excavation methods used to construct subway or other purposes (railway, utility, technological, etc.) tunnels in volatile homogeneous rocks and bound soils, and the machinery and equipment developed so far, have largely solved the major problems of excavating, securing, the removal of material, the installation of the tunnel wall and the embedding of the tunnel into the environment.

The peculiarity of the subway construction is that network design is largely determined by the modernization of public transport in the settlements developed over the centuries, the connection between the tunnel system and surface traffic hubs, and to a lesser extent by geological features.

For this reason, in Budapest, especially on the Pest side, existing and planned subway lines pass deep below groundwater and the Danube, layered with floodplains and stone benches, and in many places surface-waterproof, soaked or fine-grained water-sensitive, non-volatile stretches. .

Due to the urban built-up in these sections, the permissible size of surface subsidence is less than can be guaranteed by known excavation and construction techniques.

One of the common methods of tunnel construction is the so-called moving shield construction, where the excavation, removal and construction of the load-bearing tunnel wall is carried out under the protection of a solid tubular structure called the shield.

With differently mechanized shields - such as English PRIESTLI, Mc ALPINE, West German WESTFALIA LÜNEN, SCHAFER URBACH, DEMAG, American ROBBINS, INGERSOLL RAND, Swedish ATLAS COPCO, Soviet LENINGRAD KT Types - a common feature of mining and tunneling processes used in context and their disadvantage is that they are used only for tunneling in stable, homogeneous and practically dry soil types.

Given that the soil to be excavated is stable, it is generally unnecessary to support the forehead surface during decommissioning and prevent collapse.

The tunneling methods used by various companies in the field of stable soil and oil tunnels differ mainly in the method of excavation, the tool used for this purpose, the method of picking up and transporting the ground, and the construction, construction and installation of the load-bearing tunnel masonry. .

Also, attempts and results to date to mechanize tunneling in non-volatile, soft, water-sensitive or wet soils are well known.

One of these methods involves the use of one or both circular or alternate movements, typically with flat or conical surfaces, dismounting heads or cutting edges mounted thereon, and openings for deflecting material through a fixed or adjustable gap into the shield space. . Supporting surfaces permanently sealed throughout the front face and frictional on the front face are used. Among these, the West German company BADE method is probably one of the best known and most advanced.

There are also known attempts to mechanize tunneling in non-volatile soils using a fully enclosed and sealed shield with a fixed front face. The space in front of the shield, which is equipped for mechanized excavation, is filled with a flow of concrete slurry similar to the construction of a gap wall. Its job is to support the quarrying surface on the one hand and to transport the excavated soil hydraulically on the other hand.

A common disadvantage of all of these processes is that mechanized excavation with a completely closed, invisible front surface often results in surface cracks and unexpected water intrusions, resulting in unacceptable surface subsidence. A further disadvantage is that the manual operations necessary to safely traverse heterogeneous sections with layered, oblique, harder rock benches, or which require soil consolidation, are very complicated.

The process of the present invention is based on the recognition that non-volatile, variable-layered, heterogeneous soil physics-specific, rock-bedded, soaked, soft, water-permeable, granular, muddy, clay soils can be safely constructed and constructed without surface depressions resulting from quarrying would be beyond the allowable extent - that, if the whole or part of the front surface is at a density corresponding to the situation at hand, it is supported by radial supports providing self-adjusting elastic support and using radial quarrying.

This method allows for continuous visual inspection of the frontal surface and for immediate assessment and intervention at different stages. (Eg: application of overpressure, soil consolidation by injection or manual dismantling of critical points, etc.)

The displacement of any portion of the radial supports allows the machine to be radially disposed of the exposed front surface portion while the remaining portion of the front surface may remain as elasticly supported as necessary.

When passing through fragile soil sections, all supports can be displaced so that the entire forehead is exposed and machine-disassembled.

For the passage of heterogeneous hard stone benches with variable inclination and stratification, the process also allows the layers requiring hardening to be injected, and the hard stone benches to be freely expanded with a suitable die.

The essence of the process according to the invention is illustrated in FIG. Figure 1 is a vertical longitudinal section of the tunnel; figure front view.

187,741

The structure of the shield (1) schematically depicted is essentially an open rigid cylindrical tube at both ends. The end in the direction of travel is the cutting edge (2). This delimits the circular die surface (3). The shield (1) being built in the tunnel (4) of cargo walls ⁵ having at the opposite end. The so-called cut (5) of the shield body is advanced by resting on the built tunnel wall. In non - volatile soils, leaving the quarry face unsupported causes the front surface to collapse and fill the shield space with the existing tunnel, depending on the physical properties of the ¹ θ - flow sand or sludge. In the critical case, such a rupture may extend to the surface or result in unacceptable surface subsidence. ¹⁵

The process of the invention, tunneling from the non-thixotropic soil in each working phase of the fejtésnél the vágatásnál and the load-bearing masonry construction when also using a self-aligning radially disposed (6) homloktámasztó elements which provide support for ^two of the working face surface permanently and flexibly. The support elements (7), which can be actuated separately and together, can be closed in the space of the shield (1) by means of an articulated mechanism, whereby the whole or a part of the extraction surface can be freely dismantled. Among other things, radial headrests have the advantage of being permanently integrated into the shield structure and ready for immediate use when needed.

It is a prerequisite for the correct implementation of the radial forehead support according to the invention that the extraction also takes place in a polar coordinate system.

Radial machining also allows narrow bands to be machined into any sector, while the rest of the front surface remains resiliently supported. In critical situations, it is possible to advance the series of adjacent narrow bands. Radial machining also has the advantage that the surface so machined can also ensure that the supports are correctly positioned.

Claims (3)

CLAIMS 1. A method for excavating circular tunnels in submerged, non-volatile, varying soils by providing a permanent and flexible support for a radially perpendicular element at each stage of the tunnel construction, which can be individually and co-operatively provided with a radially perpendicular axis. 2. The method of claim 1, wherein the front face is opened or closed intermittently or completely by varying the number of supporting members. A method according to any one of claims 1 or 2, characterized in that the excavation of the soil is carried out radially on the partially or completely open face.