RU2501912C2 - Method to erect underwater tunnels - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method to erect underwater tunnels, including tunnelling of slopes and drifts, creation of a mine of arched shape, fixation of its walls and fixation of its walls and vault by monolithic reinforced concrete, backlining external hydraulic insulation from bitumen putty, a ramp and a water impermeable lock, water drainage by means of drainage trays, differing by the fact that in order to ensure efficiency of tunnelling works and higher reliability of tunnel hydraulic insulation, its length is divided into sections with open and underground methods of tunnelling. An inclined entry trench is built on an open area with minimum water level in a river by means of open works, in the end of the trench a protective horseshoe-shaped border is erected from reinforced concrete, walls are erected, the arched vault of the tunnel with rigging, on top of which they lay a hydraulic insulation jacket from Typar material and filled with removed soil, the tunnelling of the underwater section of the tunnel is carried out in a regimen of moderation by tunnelling combines in counter headways until they are joined at the design elevation, and water breakthrough in the tunnel is collected in a sump with subsequent pumping by pumps via wells to a surface interception ditch, connected with a water reservoir.

EFFECT: higher reliability of tunnel hydraulic insulation, reduced labour intensiveness and material intensity in construction.

1 tbl, 4 dwg

Description

Underwater tunnels through rivers are preferred in the presence of floods and powerful ice drifts passing at high water levels, channel instability, and also according to urban planning requirements. The listed factors are inherent in the northern rivers, mainly originating in the southern latitudes and flowing into the northeastern seas. Therefore, this invention relates to underground and underwater structures and can be used in the construction of road and rail tunnels, passable under water, mainly in the permafrost zone.

A known method of constructing underwater tunnels on the dam, including the excavation of the underground section of the tunnels, the construction of the ramp, the closed part of the tunnel under water on the dam [D. Konyukhov Use of the underground space. Textbook allowance for VU3-s. - M.: Architecture. - 2004 .-- 296 c. - C.148-156].

The disadvantage of this method is the limited scope, mainly when crossing deep water barriers, as well as the presence of possible interference and obstacles to navigation.

There is also known a method of constructing underwater tunnels buried in the bottom, including first driving an inclined section of tunnels, then an underwater section and a set of works on equipping tunnels with water inlets, a pump station and fixing their walls [D. Konyukhov Use of the underground space. Textbook allowance for VU3-s. - M.: Architecture. - 2004 .-- 296 p. - S.149-153].

The disadvantage of this method is the high cost of construction, the predominant use of a wide watercourse with flat and low banks, when overcoming small water barriers and the bed of a watercourse formed from a thickness of weak soils.

There is a method of erecting underwater tunnels, including the excavation of inclined and horizontal workings, the creation of an excavation of an arched form or the opening of workings in parts, the walls and the arch of the tunnel are secured with cast concrete and drainage using drainage trays [Volkov V.P. Tunnels and subways. - M .: Transport. - 1975 .-- 542 p. - S.244-246].

The disadvantage of this method is the unreliability of the design, which does not provide complete waterproofing of the tunnels from the penetration of water.

Closest to the invention in technical essence is a method of constructing underwater tunnels, including the excavation of inclined and horizontal workings, creating an excavation of arched form, fixing its walls and arch with monolithic reinforced concrete, tapered external waterproofing from bitumen mastic, a ramp and a waterproof shutter, drainage using drainage trays [Volkov V.P. Tunnels and subways. - M .: Transport. - 1975 .-- 542 p. - S.70-73].

The disadvantage of this method is the low efficiency of mining operations and the poor reliability of the waterproofing of the tunnel in the conditions of cryolithison, where the processes of phase fluctuations in the temperature of the environment are constantly ongoing, accompanied by constant defrosting and freezing of permafrost.

The aim of the invention is to ensure the effectiveness of mining operations and increase the reliability of the waterproofing of the tunnel.

This goal is achieved by the fact that according to the method of constructing submarine tunnels, its length is divided into sections with open and underground methods of penetration, and an inclined entrance trench is built on an open section with a minimum level of water in the river using open-cut equipment, and a horseshoe-shaped protective curb is built at the end of the trench from reinforced concrete, erect walls, arched arch of the tunnel with equipment, on top of which they lay a waterproofing jacket made of Taipar synthetic material and fill it with excavated soil, sinking odvodnogo tunnel portion are gently roadheader colliding face before docking at their design elevation, and water leakage in the tunnel is collected in the sump with the subsequent evacuation pumps through hole on a surface ditches connected to the reservoir.

In the proposed method, new features in comparison with the prototype are:

- Creation of a new technological scheme for the construction of underwater tunnels using combinations of underground and open pit mines;

- the use of a new principle for the construction of an inclined section of the tunnel by driving a deep entrance trench with the construction of a horseshoe-shaped reinforced concrete border;

- use for the conditions of the permafrost zone a new waterproofing material taipar in the construction of the tunnel, which is resistant to phase fluctuations in ambient temperature after opening permafrost;

- Creation of a new scheme for removing water breakthroughs from a tunnel through a drainage tray, sump, well, upland ditch and a reservoir.

All these new features eliminate the disadvantages of existing methods of constructing underwater tunnels under water and provide the following enhanced new positive properties:

- the use of combinations of open and underground workings reduces the construction time of submarine tunnels;

- the use of an inclined trench with a protective horseshoe-shaped curb made of concrete reduces the total cost of building tunnels and protects them from flooding when the water level in the river rises;

- protection of the tunnel from leaking water using a waterproofing jacket made of Taipar synthetic material ensures the reliability of the structure in conditions of permafrost;

- a new scheme for removing water breakthroughs from the tunnel reduces the cost of drainage due to the exclusion of a special expensive drainage scheme;

- the use of a well and a ditch in the drainage scheme improves the environmental situation in the region due to the discharge of unpolluted water into the river network.

The method is illustrated by drawings. Figure 1 - layout of the underwater tunnel in the plan; figure 2 is a cross section of an underwater tunnel; figure 3 is a longitudinal profile of an underwater tunnel; figure 4 the design scheme for determining the scope of work on the construction of an underwater tunnel.

The method is as follows.

The structures of the underwater tunnel 1 begin with a minimum level of water 2 in the river 3 (Fig. 1). Entrance trenches 4 pass from opposite banks of the river, and the excavated soil is stored in dumps 5 on board the trench. At the end of the entrance trench, a horseshoe-shaped protective border 6 made of reinforced concrete is erected above the maximum water level 7 in the river. Moreover, the entry trench 4 is driven using open-pit mining techniques - by excavators or loaders with the removal of rocks by dump trucks on board the trench. After driving and forming the entrance trench, walls 8 and the arch vault of the tunnel 9 are made of monolithic reinforced concrete (Fig. 2), after which a waterproofing jacket made of taipar 10 is laid on top of it and covered with excavated soil 5, restoring the original surface relief 11 (Fig. 3 ) The underwater section of the tunnel is driven by two oncoming faces 12 using underground work techniques - roadheaders. In the process of driving the underwater section of the tunnel, sumps 13 are created to collect water that seeps into the tunnel, which flows down the drainage tray 14. Water from the sumps 13 is pumped through the wells 15 into the upland ditch 16, from where it flows by gravity into the river network.

The technical essence and advantages of the new technical solution are disclosed by the example of an underwater tunnel passing through a river in the extreme climate of the North permafrost zone.

The initial data for the calculations are as follows:

- the width of the river, W _p = 3 km;

- the cross-sectional area of the automobile tunnel, S _t = 83.25 m ² (see below);

- the angle of inclination of the tunnel on the inclined section, α _t = 6 ° = 10 ° / _°° ;

- the cost of excavation of 1 m ³ of rocks in an open way, with _about = 3.41 dollars / m ³ ;

- the cost of mining 1 m ³ of rocks by underground, with _p = 10.23 dollars / m ³ ;

- the cost of re-excavation of 1 m ³ of rocks from the calculation, with _e = 0.2 · s _about = 0.7 dollars / m ³ .

The calculation scheme for determining the scope of work on the construction of an underwater tunnel is shown in figure 4.

The calculations are performed in the following sequence:

1. The total length of the underwater tunnel, L _t ,

L _t = L _g + 2L _n ,

where L _g , L _n - respectively the length of the horizontal and inclined sections of the tunnels, km, L _g = W _p = 3 km:

L _n = N _g · α _t

N _g - the depth of the tunnel, m;

H _g = h _b + h _p + h _s ,

h _b - the height of the river bank, m, h _b = 20 m; h _p - average river depth, m; h _p = 8 m; h _s - the depth of the tunnel from the bottom of the river, m; h _s = 14 m;

L _n = N _g · α _t = (20 + 8 + 14) · 10 = 420 m,

whence L _t = 3000 + 2 · 420 = 3840 m.

2. Justification of the parameters of the road tunnel.

As an example, a two-lane automobile tunnel, the cross-sectional area of which according to the regulatory data of the literature [Volkov V. Tunnels and subways. - M .: Transport. - 1975 .-- 542 p. - S.63-65] is calculated by the formula:

S _t = W _t · H _t ,

where W _t - the width of the double-track automobile tunnel, m;

N _t - the average height of the tunnel, m

W _t - 8 m + 8 m + 1 m + 1 m + 0.25 m + 0.25 m = 18.5 m,

where 8 m is the width of the carriageway in one direction, m;

1 m - the width of the service sidewalk, m;

1 m - the gap between the cars in the two-lane direction, m;

0.25 m - the width of the protective strip on both sides of the roadway, m.

The average height of the car tunnel, N _t = 4.5 m, then

S _t = W _t · N _t = 18.5 · 4.5 = 83.25 m ² .

3. The volume of work on the sinking of the underwater section of the tunnel - V _g ,

V _g = L _g S _t = 3000 m · 83.25 m ² = 249750 m ³ .

4. The volume of work on the sinking of the inclined section of the tunnel - V _n

V _n = V _but + V _np ,

where V _but - the amount of work on driving an inclined section of the tunnel, performed by an open method, m ³ ;

V _np - the volume of work on driving an inclined section of the tunnel, performed underground method, m ³ .

In an open way, a section of the tunnel passes in the form of an entrance trench to a depth of the water level in the river.

Then the volume of work on its penetration will be equal to:

V _but = L _but · h _b / 2 ^· W _tr ,

where L _but - the length of the entry trench, m;

W _Tr - the width of the entrance trench, m, W _Tr = 30 m

L _but = h _b · α _t = 20 · 10 = 200 m

V _but = 200 · 20/2 · 30 = 60,000 m ³ .

The length of the inclined underground section of the tunnel - L _np ,

L _np = L _n -L _but = 420-200 = 220 m.

Scope of work on driving an inclined underground section of the tunnel,

V _np = 2 · L _np · S _t = 2 · 220 · 83.24 = 36626 m ³ .

Hence,

V _n = V _but + V _np = 60,000 + 36626 = 96626 m ³ .

5. The cost of tunneling - Z _Fri :

З _пт = З _по + З _пп ,

where Z _on - the costs of tunneling section of the tunnel, performed in an open way, dollars;

З _п - underground tunneling costs, USD,

3 _by = C _o · V _by = 3.41 · 60,000 = $ 204,600

Z = C _{pp f} · V _pp = 10.23 · 36626 = 374,684 dollars.

where С _p ≃З · С _о = 3.41 · 3 = 10.23 dollars / m ³ ,

whence, Z _Fri = 204600 + 374684 = 579284 dollars.

6. The cost of the construction of tunnel lining.

The design of lining made of monolithic concrete, the main parameters of which according to the literature [Volkov V.P. Tunnels and subways. - M .: Transport. - 1975 .-- 542 p. - S.69-77] amounted to:

- thickness of the lining of concrete, m = 0.6 m;

- concrete volume per 1 linear meter m lining, ΔV = 8.9 m ³ .

Then the total concrete consumption Q _b for the construction of an underwater tunnel of length L _t = 3840 m is equal to,

Q _b = L _t · ΔV + ΔQ,

where ΔQ - concrete consumption for the carriageway of the tunnel with a thickness of Δh = 0.15 m, m ³ ;

ΔQ = Δh · W _t · L _t = 0.15 · 18.5 · 3840 m = 10656 m ³ ,

Q _b = 38408.9 + 10656 = 44832 m ³ .

The cost of laying concrete Z _b will be:

З _b = С _b · Q _b = Q _b · 44832 = $ 4.53 million

where C _b - the cost of laying 1 m of concrete, dollars,

With _b = 101 dollars / m ³ (3032 rubles / m ³ according to OAO Yakutcement).

The cost of waterproofing by covering the tunnel lining with taipar is determined on the basis of the cost of 1 m ^{2 of} film equal to 1.43 dollars / m ³ (43 dollars / m ² ). At the same time, the use of a taipar as a reinforcing canvas for the tunnel lining increases the reliability of waterproofing not only due to its inherent properties, but also the acquisition of additional positive qualities:

- taipar does not decay and does not decompose;

- has a high resistance to tearing and puncturing, chemical resistance and filtering properties;

- increases the working life of structures;

- does not absorb water and performs a reinforcing function;

- prevents the penetration of small particles into the structure, and the deposition of a large number of them on the surface creates an impermeable film;

- increases the strength of waterproofing when laying it together with bitumen emulsion.

7. The calculation of the cost of covering the tunnel with taipar is as follows. Taypar consumption on 1 running. m production R _t will be:

R _t = 2W _t + 2H _t = 2 · 18.5 + 2 · 4.5 = 46 m.

For the entire length of the tunnel LT, the consumption of the taipar ΣP _t is

ΣР _t = Р _t · L _t = 46 · 3840 = 176640 m ² .

Then the costs of covering the tunnel with taipar will be equal to:

З _t = ΣР _t · С _t ,

where C _t is the cost of 1 m ^{2 of} taipar film, C _t = 1.43 dollars / m ² (43 rubles / m ² ).

З _т = 176640 · 1.43 = 252595 dollars

The total costs for the construction of tunnel lining - W _is,

Z _then = Z _b + Z _t = 4530000 + 252595 = 4782595 dollars.

Total costs for the construction of the tunnel:

Z _tone = Z _Fri + Z _b + Z _t = 579284 + 4530000 + 252595 = 5361879 dollars = 5.36 million dollars

3 _tons = $ 5.36 million = 178.7 million rubles.

The expected economic efficiency from the introduction of the underwater tunnel is calculated in accordance with the bridge. According to the source [Androsov A.D., Semenov V.A., Zakharov Yu.V. The feasibility of building underground tunnels under the Lena River. - M.: MGGU. - 2006. - GIAB No. 2. - S.175-179] the cost of 1 km of a bridge with two-lane automobile traffic will be 0.5 billion rubles. Then the cost of a bridge 3 km long will be equal to:

With _m = 3.0 0.5 = 1.5 billion rubles. = $ 50 million

Therefore, the expected reduction in capital costs from the introduction of the submarine tunnel - E will be:

E = C _m -C _t = 50.0-5.36 = $ 44.6 million

Table 1 shows the comparative technical and economic indicators for the implementation of the recommended option for the construction of a tunnel under water in a permafrost zone.

Table 1 The main technical and economic indicators of the construction of the submarine tunnel in comparison with bridge crossings №№ The name of indicators Traditional option (bridge) Recommended Option (Tunnel) one The width of the river, km 3.0 3.0 2 The length of the bridge, km 3.0 - 3 Tunnel length, km - 3.84 four The cost of driving a two-lane automobile tunnel, thousand dollars 397,056 5 The cost of the construction of tunnel lining of concrete, thousand dollars 4782.6 6 The cost of covering the tunnel with waterproofing material (taipar), thousand dollars 252,595 7 The total cost of the construction of the tunnel, million dollars 5.36 8 Costs for the construction of a two-lane automobile bridge, $ million 50,0 9 The expected reduction in capital costs from the introduction of the submarine tunnel, $ million 44.6

Consequently, the expected reduction in capital costs from the introduction of the submarine tunnel amounted to $ 44.6 million, i.e. 1 km of tunnel length compared to the bridge crossing provides a reduction in capital costs of $ 11.61 million. The calculations do not take into account operating costs, since they are almost the same in both cases and will not have a significant impact on reducing the efficiency of tunnel crossings.

Claims (1)

A method of constructing underwater tunnels, including the excavation of inclined and horizontal workings, the creation of an excavation of an arched shape, the fastening of its walls and arch with monolithic reinforced concrete, the tapered external waterproofing from bituminous mastic, a ramp and a waterproof shutter, drainage using drainage trays, characterized in that, for the purpose of ensure the effectiveness of mining operations and increase the reliability of the waterproofing of the tunnel, its length is divided into sections with open and underground methods of penetration, and in open learning They build an inclined entrance trench at a minimum level of water in the river using open-casting techniques, build a horseshoe-shaped protective border made of reinforced concrete at the end of the trench, erect walls, an arch vault of the tunnel with accessories, on top of which they lay a waterproofing jacket made of Taipar synthetic material and fill it with excavated soil, tunneling the underwater section of the tunnel is driven in a gentle mode by roadheaders with oncoming faces until they dock at the design elevation, and water breakthroughs in the tunnel are collected in a sump followed by pumping pumps through wells to a surface ditch ditch connected to a reservoir.

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