New soil abrasion testing method for soft ground tunneling applications (original) (raw)

New Test Methodology for Estimating the Abrasiveness of Soils for TBM tunneling

Tunnel excavation using tunnel boring machines (TBMs), has become increasingly common in recent years, despite the fact that precise evaluation of certain risks have not kept pace with the use of these machines. One of the risks easily overlooked by Engineer and Contractor alike are the effects of abrasive ground on the costs and schedule of a given project. The impacts of worn and damaged TBM cutter heads have been observed on hundreds of tunnel projects around the world. It would appear that a reliable prognosis of the abrasiveness of soils on a project would be of great importance for designers, clients and contractors alike. Several well acknowledged test and prognosis methods already exist for rock, however there is only very limited knowledge available to describe the abrasiveness of soil and its impact on soft ground TBMs. This paper will examine approaches to this problem and suggest a new approach based on a current project undergoing design.

Predicting the abrasivity of in-situ like soils

Tunnels and Tunnelling International, 2012

Increased urbanisation constantly demands more infrastructure, often requiring the construction of tunnels and facilities underground. The complexity of Tunnel Boring Machine (TBM) function and the complicated nature of soft ground and soil working environments make the estimation of wear a challenging issue. The following tests and procedures are included in the original contribution to this PhD study; 1) an overview and presentation of various laboratory methods designed to estimate and assess soil abrasivity in connection with soft ground TBM tunnelling, 2) the development of models, based on simplified laboratory tests, for the estimation of TBM tool life when excavating soil and soft ground, 3) the development of the Soft Ground Abrasion Tester (SGAT), designed to increase the validity of simplified estimation tools. The simplified laboratory tests incorporate the Soil Abrasion Test (SAT™), quartz content measurements, and the geotechnical uniformity index Cu. Test results have...

Abrasivity of soils in TBM tunnelling

TBM excavation has become increasingly common, despite the fact that precise evaluation of certain risks has not kept pace with the use of these machines. One of the risks easily overlooked by Engineer and Contractor alike are the effects of abrasive ground on the costs and schedule of a given project. The impacts of worn and damaged TBM cutterheads have been observed on hundreds of tunnel projects around the world. It would appear that a reliable prognosis of the abrasiveness of ground on a project would be of great importance for designers, clients and contractors alike. Several well acknowledged test and prognosis methods already exist for rock; however, there is only very limited knowledge available to describe the abrasiveness of soil and its impact on wear on soft ground TBMs. This three-part article examines existing approaches to the problem and suggests a new approach based on a current project undergoing design. Defining wear For the purposes of the following discussion it...

Soil abrasiveness for EPB-TBM along Tehran metro tunnel line 7, Iran

2015

Full-face shielded tunnel boring machines (TBM) including earth pressure balance (EPB) shields have been used almost exclusively for soft ground tunneling because of the many advantages the offer in comparison to the conventional methods. The total number of EPB-TBMs that were utilized for tunneling between 2005 and 2010 is approximately 350 units worldwide as reported by [1]. These machines encounter a wide range of geological conditions and hazards. One of the most critical adverse conditions is encountering abrasive soils and excessive wear on the cutting tools and the cutterhead as has been reported in many EPB tunneling projects worldwide [2], [3]. Inspection and maintenance of cutting tools below the groundwater table is usually performed under hyperbaric conditions where air pressure is used to provide tunnel face stability. This involves creating a plug at the face, removing the spoils (muck), applying compressed air, and allowing the crew into the cutting chamber via an air...

Modeling of soil-tool abrasive wear processes in mechanized tunneling

2021

Beim maschinellen Tunnelbau handelt es sich um eine Bauweise, welche in den letzten Jahrzehnten aufgrund der hohen Anforderungen, welche an den Ausbau der Infrastruktur in Großstädten gestellt wurde, auf ein großes Interesse gestoßen ist. Ein entscheidender Faktor um die Tunnelbauprojekte mit Tunnelvortriebsmaschinen (TVM) effizient zu gestalten ist es den abrasiven Verschleiß der Maschinenkomponenten beim Abbauprozess zu verstehen und vorherzusagen. Dies stellt das Hauptthema der vorliegenden Arbeit dar. In dieser Arbeit wird ein neuartiges Verschleißmodell zur Vorhersage der Abrasionsrate entwickelt. Dieses basiert auf der Idee die Ergebnisse einzelner Ritzversuch auf die gesamte Abrasionsrate einer Mischung aus abrasiven Partikeln zu übertragen. Das eingeführte Verschleißmodell führt zu geschlossenen Formbeziehungen und vermeidet aufwendige sowie rechenintensive 3D-Verschleißsimulationen.

Abrasive Wear in Ground Engaging Tools and Its Remedial Measures

International Journal for Research in Applied Science & Engineering Technology (IJRASET), 2022

Wear is the degradation of material under plethora of service conditions and is considered as one of the major issue of the material used in engineering. So far, various types of wear have been recognized such as erosive wear, surface fatigue, fretting wear, adhesive wear, abrasive wear and sliding wear. Wear by abrasion accounts for more than 50% of the wear failures occurring in industries. Hard abrasive particles penetrate the components and cause damage in the form of material loss. The components of machines working under severe conditions the soil engaging part of the earth-moving machinery, and various agricultural implements experience sever wear. The wear in agricultural equipments and tillage is the main problem. For combating with wear problem various methods have also been developed such as hardfacing, cryogenic treatment, coating and heat treatment of components, which are chosen on the basis of various conditions under which the component has to perform the desired function. Hardfacing and heat treatment is commonly used to resist this failure, also considered as most appropriate and economically sound process for improving the life of tillage tool at farming level. In the present paper author as made the effort to review various types of wear and remedial measures.