UNITRACC - Underground Infrastructure Training and Competence Center

Definitions Trenchless Method of Construction

Trenchless construction technique:
Any technique for constructing pipelines in the ground without opening trenches [DINEN12889:2000].

(Image: Shield machine arriving in the target shaft)

(Image: Microtunnelling machine with pneumatic spoil removal (method AVP [FI-Herreb]) - Scraper cutting head with view of the rotary vane lock behind the excavation chamber)

(Image: Microtunnelling machine with auger spoil removal ? cutting head)

Underground …

May 18, 2020

Definitions

May 18, 2020

Classification of trenchless construction techniques

(Image: Manned techniques) manned	(Image: Unmanned techniques) unmanned
(Image: Steerable techniques) steerable	(Image: Steerable techniques) steerable	(Image: Non-steerable techniques) non-steerable
(Image: Soil removal techniques) soil removal	(Image: Soil removal techniques) soil removal	(Image: Soil displacement techniques) soil displacement	(Image: Soil removal techniques) soil removal	(Image: Soil displacement techniques) soil displacement

May 18, 2020

Definition Manned/unmanned technique

(Image: Manned techniques)

Manned technique:
Technique involving the use of personnel working in the excavated bore during installation [DINEN12889:2000].

(Image: Unmanned techniques)

Unmanned technique:
Technique avoiding the use of personnel working in the excavated bore during installation [DINEN12889:2000].

May 18, 2020

Definition Steerable / non-steerable techniques

(Image: Steerable techniques)

Steerable techniques:
Techniques which allow for a correction of the direction of the cutting head, the steel pipe joint or auger flight [Stein05a].

(Image: Non-steerable techniques)

Non-steerable techniques:
Techniques which do not allow for a correction of the direction of the cutting head, the steel pipe joint or auger flight [Stein05a].

May 18, 2020

Definition soil removal / soil displacement techniques

(Image: Soil removal techniques)

Soil removal techniques:
Jacking pipes are jacked either dynamically or statically from a starting shaft to a target shaft whereby the soil or rock material loosened by the jacking is transported away either continuously, in intervals or after the boring [Stein05a].

(Image: Soil displacement techniques)

Soil displacement techniques:
Static or dynamic jacking of jacking pipes by displacement of the in situ soil …

May 18, 2020

Overview of the methods of trenchless installation of cables and pipelines by jacking or drilling

(Image: Overview of the methods of trenchless installation of cables and pipelines by jacking or drilling)

May 18, 2020

Overview of techniques

May 18, 2020

Advantages compared to the open-cut method of construction

Advantages and disadvantages of trenchless installation

(Image: Pros and cons)

Advantages of trenchless construction:

groundwater lowering not necessary
relatively small excavated soil volume
only in the region of the starting and target pits road breaking necessary
low impact of traffic and thus less traffic jams and strain of residents due to exhaust fumes
less damage of neighbouring structures

(Image: Pros and cons)

Disadvantage of trenchless technology:

possibly higher costs with reference …

May 18, 2020

Advantages compared to the open-cut method of construction

Jan 31, 2023

NA-21 - Trenchless Construction: Introduction

Today, the installation of gas, water, and wastewater pipelines is still predominantly carried out using the open trench installation. In view of the numerous disadvantages associated with this method, it is imperative that in the future trenchless pipeline construction be considered much more strongly as an alternative in the planning and construction of sewers and pipelines. For a better understanding of the complexity of the inner-city subsoil, this module provides a brief introduction to infrastructures in the urban subsoil.

After completing this module, you will have knowledge regarding:

prerequisites for a functioning infrastructure;
options for new pipeline construction;
procedures for trenchless pipeline construction; and
advantages over the open cut method.

Jul 25, 2024

Microtunnelling with auger spoil removal

Removal of the Spoil

The spoil loosened at the working face with the aid of the cutting head is transported to the starting shaft by the spiral conveyor and is there collected in a spoil bucket. Using lifting tackle, this is lifted to the surface when full at determined intervals, usually after jacking a pipe piece. The pressure at the working face is mechanically balanced by the cutting head or by means of the soil plug that is formed in the front section of the conveyor …

Jul 25, 2024

Microtunnelling with auger spoil removal

Drive variants of the cutter head

(Image: Microtunnelling with auger spoil removal in single phase jacking - Variant: driving the cutting head with the spiral conveyor)

(Image: Microtunnelling with auger spoil removal in single phase jacking - Variant: direct driving of the cutting head and separately driven spiral conveyor)

Drive variants of the cutting head:

Variant A: driving the cutting head with the spiral conveyor
The spiral conveyors (auger rods) and cutting head are fixed …

Jul 25, 2024

Microtunnelling with auger spoil removal

Design of the cutter

(Image: Example of cutting head driven with the spiral conveyor [Becke96])	(Image: Example of cutting head driven with the spiral conveyor [FI-Herreb])
(Image: Example of cutting head driven with the spiral conveyor [FI-Wirthb])	(Image: Example of cutting head driven with the spiral conveyor [FI-Schrö])

Jul 25, 2024

Microtunnelling with pneumatic spoil removal

Removal of the Spoil

A distinction is made with regard to the discharge system, between

Suction plants
Pressure plants

The transfer point of the spoil to the respective discharge system, which at the same time acts as the point of pressure-tight separation between the excavation and crusher chamber, can be designed in a number of ways.

Rotary vane lock

(Image: HERRENKNECHT AVP method - View of the rotary vane lock behind the excavation chamber [FI-Herreb])

Spoil valve

Jul 25, 2024

Microtunnelling with pneumatic spoil removal

Design of the cutter head

Microtunnelling machines with pneumatic spoil removal are used with standard cutting heads as well as rock cutting heads so that the same areas of application are valid in soils and rock as with hydraulic spoil removal to [Becke96] [Wilhe99a].

(Image: Microtunnelling machine with pneumatic spoil removal (method AVP [FI-Herreb]) - Scraper cutting head with view of the rotary vane lock behind the excavation chamber)

Jul 25, 2024

Microtunnelling with hydraulic spoil removal

Design of a microtunnelling machine with hydraulic spoil removal

(Video: Integrated high-pressure flushing system in the crusher space of the AVN microtunnelling machine)

Jul 25, 2024