USING A PIPE JACKING EQUIPMENT.

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Technical Field

The present invention concerns an innovative technique providing a one-pass operation that, while vertically excavates through soil formation, installs riser segments from underground to upward.

In the following, such a technique will be also called as: “Riser Concept”.

According to the invention, it is provided a pipe jacking equipment for vertically pushing the riser pipe from underground to pass upwards through soil formations to waterbody, air intake, terrain surface or the like. The invention can be applied either in traditionally bored tunnel or in tunnel bored by Tunnel Boring Machine (TBM) . Background Art

Heretofore, several methods have been designed for excavating vertical or slightly inclined bore holes from a gallery, shaft or like at one level to a gallery, shaft or like at another level, but no previous methods permit to build vertical risers from an underground lower level to upper level, through soil, especially in underwater applications (see table below).

According to the table, no existing method and apparatus permit to construct vertical risers with permanent lining, excavating bottom-up through soil from underground position.

In view of the above, a first object of the invention is to provide a method and apparatus conceived to provide one-pass operation of soil excavation and riser segments permanent installation in vertical risers, excavating upwards from underground passes through soil by means of a pipe jacking equipment.

A second object of invention is to provide a method and apparatus to displace and remove the soil by a displacement head, equipped by hydro-demolition system, to allow weakening dense soil and a soil discharge line to extract excavate soils.

A third object of invention is to provide a method and apparatus for providing the precise settle of a keystone launching segment connected with a displacement head. This aim is achieved by using special segment rings, provided by slotted holes or the like, which enable an on-site rotational adjustability of the keystone launching segment.

A fourth object of invention is to provide a method and apparatus for installing riser segments as permanent lining of the vertical riser.

A fifth object of invention is to provide a method and apparatus configured and designed for underwater application by means of sealing systems.

Summary of Invention

The present invention relates to the technical field of earth boring and more particularly relates to a method and apparatus wherein a pipe jacking equipment is provided, to install vertical risers by pushing upward riser segments into soil formations, from an underground pass to an upper level. The excavation and removal of the soil is achieved by a displacement head, equipped with a hydro-demolition system and a soil discharge line.

According to the invention, said displacement head is fastened to a keystone launching segment, equipped with a sealing system configured to connect the riser and the tunnel, to guarantee a watertight connection.

The above objects and further aims are obtained according to the present invention by providing a pipe jacking equipment that vertically push upwards the riser, divided into segments, from underground position to upper level through soil formation, even in underwater applications.

This invention is further provided with sealing systems configured to allow underwater applications and to guarantee a watertight connection between the segments of the riser themselves.

Brief Description of Drawings

The invention will be more readily understood from the following detailed description, with reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown.

In the drawings:

Figure l is a schematic cross section of a preferred embodiment of the invention showing installation stages of riser segments.

Figure 2 is a schematic cross section according to fig.1 showing an overview of riser segments installation.

Figure 3 shows, in greater detail, the schematic cross section of last drawing of fig. 1. Figure 4 is a schematic longitudinal section showing an overview of a plurality of riser segments installation.

Figure 5 is a schematic cross section showing the special segment rings: the positioning segmental ring and the launching segmental ring.

Figure 6 shows, in greater detail, the schematic longitudinal section of pipe jacking equipment.

Figure 7 is a schematic comparison of construction phases in a known typical project in rock foundation and in a submarine outfall tunnel according to the present i nvention .

Figure 8 is a schematic comparison of construction phases in a known typical project in soil foundation and in a submarine outfall tunnel according to the present i nvention .

Figure 9 is a schematic of two side views of known submarine outfall plants (P. Tate - S. Scaturro - B. Cathers, 2016).

Figure 10 is a tunnel -diffuser cross section of known Boston Outfall project, showing the offtake tunnel (Eisenberg & Brooks, 1992).

Description of Embodiments

In case of applying the invention in TBM tunnels (Figs. 1-5), the method according to the “Riser Concept of the present invention provides initially to install two special segment rings: a positioning segmental ring (5) and a launching segmental ring (4). Considering the direction of the TBM advance, the first ring is the positioning segmental ring (5), and the second one is the launching segmental ring (4), characterized by a keystone launching segment (3).

A displacement head (2) is fastened to keystone launching segment (3), which has previously been placed in the desired position for the installation of the riser (7).

According to a peculiar feature of the invention, the correct position of keystone launching segment (3) is adjustable by regulating the rotation of said special segment rings through special slotted holes (19) or the like for the longitudinal connection between the special rings (4, 5). Said slotted holes, or the like, enable an on-site rotational adjustability of the position of keystone launching segment (3).

A sealing system (6), comprising lip gaskets (6A) and additional emergency seals (6B) , is configured to ensure the water tightness between riser (7) or displacement head (2) and keystone launching segment (3).

According to the method of the present invention: a) A pipe jacking equipment (1) is positioned underneath said keystone launching segment (3) and

b) A riser initial segment (7A) is placed onto a thrust platform (14);

c) Said riser initial segment (7A) is connected to the displacement head (2) and is hold in the desired position by a pipe clamp (8) and then displacement head

(2) is disconnected from keystone launching segment

(3).

d) A high-pressure water system (17) and a discharge line system (18) are hooked up to displacement head (2) passing through riser initial segment (7A) .

e) The pipe jacking equipment (1) starts to drive/push riser initial segment (7A) through the soil, by means of a trust platform (14) and of a hydro-demolition system of displacement head (2) provided with nozzles configured to spray pressurized water to weaken the soil structure in the penetration area of displacement head (2) .

f) The thrust force is uniformly transferred to the tunnel structure by a load distribution system (15). g) A spacer (9) is placed under the riser initial segment (7A) to drive the segment trough the soil up to the required elevation;

h) In this position, riser initial segment (7A) is blocked by pipe clamp (8),

i) The spacer (9) is removed and a riser standard segment (7B) is placed on the trust platform and connected to the previous one.

These operations are repeated up to reach the desired elevation when the last segment, a riser ending segment (7C), has to be installed. Such last element is provided with two flanges: one for the permanent connection with keystone launching segment (S) and the other one to fasten a temporary bulkhead (11).

Before removing displacement head (2) from the top of riser initial segment (7A) , said temporary bulkhead (11) or the like must be installed at the bottom of riser ending segment (7C) to prevent water from entering in the tunnel .

The final step would be the removal of displacement head (2), the installation of diffuser (10) or the like at the top riser initial segment (7A) and the removal of the temporary bulkhead (11) or the like from the bottom of riser ending segment.

According to the present invention:

All risers comprise at least three segments: riser initial segment (7A) , riser standard segment (7B) and riser ending segment (7C) .

All the riser segments joints are designed and configured in order to: guarantee the desired structural capacity; avoid damage on the interface of riser segments

(7) and sealing system (6) during the pushing operation; ensure water tightness, maximum assembly speed, constructability in an underground working space.

For all jacking operations, before to apply the thrust, pipe clamp (8) is opened to drive riser segment into the soil and after to apply the thrust, pipe clamp

(8) is closed to hold riser segment.

High Pressure water system (17) and discharge line system (18) must be disconnected from displacement head (2), passed through each riser segment and reconnected to displacement head (2), before activating the pipe jacking equipment (1).

A preferred embodiment designed to carry out the Riser Concept of the present invention will hereinafter be described, with reference to a non-limitative application thereof.

A submarine outfall is a pipeline or tunnel that discharges municipal or industrial wastewater, storm water, combined sewer overflow or brine effluent from a wastewater treatment plant or desalination plant into a waterbody. The wastewater treatment plant treats to discharge positively buoyant effluent from a wastewater treatment plant, while the desalination plant treats to discharge negatively buoyant effluent (Fig 9).

Both schematics show an inclined tunnel from the wastewater plant, the outfall tunnel and a diffuser comprising several risers with outlet nozzles on its top, through which the wastewater is diffused under the water surface (P. Tate - S. Scaturro - B. Cathers, 2016).

In typical submarine outfall tunnel projects in rock foundation, three main construction stages are executed: the underground tunnel, the maritime offshore risers and the underground offtake adits. In terms of schedule, the installation of risers is performed independently from the execution of the underground tunnel (Fig 7-la) while the offtake adits start after the completion of the previous two (Fig 7-2a & 7-3a) .

Usually, the installation of the diffusion risers represents one of the most critical activities; in fact, this is performed through a multistage offshore work (Fig 7-la): initially, the bed sediment next to the riser is dredged, then a jack up drilling vessel is floated into position to jack up over riser holes positions, where a drilling template is used to ensure the locations. For each drilling phase, if required, a permanent casing is placed and the annular void between the drilled hole and the casing is filled with grout. Once the required level is achieved, the riser is lowered to be installed, grouted, and capped.

The connection of the offshore work to the underground work represents a challenging operation: “probe holes are drilled from the tunnel to ascertain the location of the pre-installed risers and to drain the risers of ballast water”, then the offtake adits are excavated to expose the risers (Fig 7-2a), which afterwards are cut and permanently linked to the tunnel through an elbow section (Fig. 7-3a & Fig. 10).

In typical submarine outfall tunnel projects in soil foundation, three main construction stages are executed: the underground tunnel , the maritime transition shaft and a diffusion pipeline equipped by risers anchored on the waterbody bed.

In terms of schedule, the connection of diffusion tunnel equipped by risers (Fig. 8-3a) is performed after the execution of the underground tunnel (Fig. 8-la) and maritime transition shafts (Fig. 8-2a) .

Typically, the connection between tunnel and the transition shaft (Fig. 8-2a) and the connection between the transition shaft and the diffusion pipeline (Fig 8-3a) , represent the most critical activities, performed through a multistage offshore work.

In submarine outfall tunnel projects, adopting the solution of the Riser Concept according to the present invention, the construction stages are simplified and in general two main construction stages are executed: the excavation of the tunnel and the construction of the risers from inside the tunnel, both underground (Fig.7b and 8b). In terms of schedule, the installation of risers (Fig.7-2b and 8-2b) is performed after the execution of the tunnel (Fig.7-lb and 8-lb).

Then, in the non-1 imitative embodiments thereof sub marine outfall project construction, the adoption of Riser Concept provides several benefits and advantages, such as: 1. Elimination of several works:

a. maritime offshore works, i.e. dredging of the bed sediment, drilling of a riser hole, installation of permanent casing, grouting by a vessel; or, dredging of the bed sediment, construction of underwater foundation, underwater installation of pipes.

b. underground activities, i.e. riser probe drilling, drill -and-blast adits excavation, installation of permanent lining and grouting; or, connection between tunnel and transition shaft, connection between transition shaft and diffusion tunnel.

2. Elimination of various maritime operations:

a. Avoidance of potential construction delays, due to suspension of maritime operations, which can be inevitably induced by marine conditions.

b. Minimization navigation traffic disruptions.

c. Mitigation of negative environmental impacts caused by dredging and drilling activities, such as may be destruction of habitats, suspension of sediments, resettling of fishes, and displacement of infauna and marine plants.

3. Attaining a reduction of both construction cost and operational cost:

a. During construction: the total cost of the project is reduced due to the elimination of several complex works, and substantial reduction of maritime operations ;

b. During the operational life: the hydraulic performance inside the tunnel is much improved, as encountered hydraulic losses are less, with a reduction of energy consumption.

While a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.

While a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the scope of the following claims. LEGEND

(1) Pipe Hacking Equipment

(2) Displacement Head

(3) Keystone Launching Segment

(4) Launching Segmental Ring

(5) Positioning Segmental Ring

(6) Sealing System

(6A) Lip Gaskets

(6B) Additional Emergency Seal

(7) Riser

(7A) Riser Initial Segment

(7B) Riser Standard Segment

(7C) Riser Ending Segment

(8) Pipe Clamp

(9) Spacer

(10) Diffuser

(11) Temporary Bulkhead

(12) Tunnel

(13) Upper Stabilizer Frame

(14) Thrust Platform

(15) Load Distribution System

(16) Railway Tracks

(17) HP Water System

(18) Discharge Line System

(19) Slotted Holes

(a) TBM tunnel excavation

(b) Offshore riser drill

(c) Underground offtake adit drill -and-blast

(d) Diffuser installation

(e) Waterbody bed dredge

(f) Transition shaft and TBM tunnel connection

(g) Diffusion pipeline connection