Filip Dahl - Academia.edu (original) (raw)
Papers by Filip Dahl
Increased urbanisation constantly demands more infrastructure, often requiring the construction o... more 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...
ABSTRACT Tunnelling by use of Tunnel Boring Machine (TBM) is gaining a greater presence as a suit... more ABSTRACT Tunnelling by use of Tunnel Boring Machine (TBM) is gaining a greater presence as a suitable excavation method. Disc cutter consumption has a strong influence on performance and cost when using TBMs and the influence becomes even more relevant in hard rock. Furthermore, good predictions of TBM performance and cost facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory assessments are needed. A new abrasivity test method called Rolling Indentation Abrasion Test was developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than traditionally used methods by introducing wear by rolling contact on intact rock samples.
Tunnels and Tunnelling International, 2012
Increased urbanisation constantly demands more infrastructure, often requiring the construction o... more 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...
Weakness zones or faults containing swelling clay represent a challenging situation in hard rock ... more Weakness zones or faults containing swelling clay represent a challenging situation in hard rock tunnelling. When excavating in such zones, failures have occurred occasionally even though particular precautions have been taken. Instability has been encountered during tunnel excavation and sometimes also long after tunnel completion. One of the most recent cases of failure, the rock fall at the Hanekleiv road tunnel in southeast Norway, occurred ten years after tunnel completion. The rock fall was in a fault zone where swelling clay had been identified, about 1.1 km from the northern tunnel entrance of the southbound tube. Cracks had been detected in the applied shotcrete at the fault zone during tunnel excavation. In one major weakness zone containing swelling clay at the Finnfast subsea tunnel, monitoring was carried out by the Norwegian Geotechnical Institute (NGI). Strain gauges and load cells were installed in the reinforced shotcrete rib near the crown and at springlines of the...
Weaknesses zones consisting of sheared and fractured rock mass have a swelling potential in the p... more Weaknesses zones consisting of sheared and fractured rock mass have a swelling potential in the presence of clays rich in montmorillonite. When it comes to intact rocks there are questions regarding both the swelling potential and the main reasons for swelling in the different rock types. This is experienced in several projects, where swelling of intact rock has been different than what was expected. To better understand what is causing the behaviour of intact rock when exposed to water a comprehension on the water impact on the swelling potential is required. For clay minerals the swelling mechanisms and factors influencing on the swelling potential is explained and confirmed by comprehensive research. Four types of clay minerals are discussed to describe the swelling potential of these minerals in contact with water. The extensive laboratory work performed for this thesis addresses a study on the expansive character of intact rock. Three different rock types are tested; alum shale...
Rock Mechanics and Rock Engineering, 2015
The tunnel boring machine (TBM) method has become widely used and is currently an important prese... more The tunnel boring machine (TBM) method has become widely used and is currently an important presence within the tunnelling industry. Large investments and high geological risk are involved using TBMs, and disc cutter consumption has a great influence on performance and cost, especially in hard rock conditions. Furthermore, reliable cutter life assessments facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory tests for rock abrasivity assessments are needed. A new abrasivity test method by rolling disc named Rolling Indentation Abrasion Test (RIAT) has been developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than the traditionally used methods. Wear by rolling contact on intact rock samples is introduced and several rock types, covering a wide rock abrasiveness range, have been tested by RIAT. The RIAT procedure indicates a great ability of the testing method to assess abrasive wear on rolling discs. In addition and to evaluate the newly developed RIAT test method, a comprehensive laboratory testing programme including the most commonly used abrasivity test methods and the mineral composition were carried out. Relationships between the achieved results from conventional testing and RIAT results have been analysed.
Geotechnical Testing Journal
Tunnelling and Underground Space Technology
Tunnelling by use of Tunnel Boring Machine (TBM) is gaining a greater presence as a suitable exca... more Tunnelling by use of Tunnel Boring Machine (TBM) is gaining a greater presence as a suitable excavation method. Disc cutter consumption has a strong influence on performance and cost when using TBMs and the influence becomes even more relevant in hard rock. Furthermore, good predictions of TBM performance and cost facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory assessments are needed. A new abrasivity test method called Rolling Indentation Abrasion Test was developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than traditionally used methods by introducing wear by rolling contact on intact rock samples.
The new NTNU Soil Abrasion Test (SAT) is a further development of the existing abrasion tests for... more The new NTNU Soil Abrasion Test (SAT) is a further development of the existing abrasion tests for rock (Bruland et al. 1995). Compared with the AVS test (T&TI April, p48), only one detail has been changed: a sieved soil sample <1mm is used instead of crushed rock powder <1mm. Test procedure To enable comparison with previous test results, and to take advantage of the extensive NTNU database it is considered important to follow the standardised NTNU abrasion test procedures as closely as possible. The following preparation of soil samples is therefore recommended, and has been followed for the testing described: In order to reduce or avoid changes of the original properties, soil samples should be dried gently in a ventilated oven at 30˚C for 2-3 days. The following techniques should be used after drying in order to disintegrate and separate particles for the abrasion powder: 1) Disintegration by use of a soft hammer. 2) Sieving with steel balls as gentle milling/disintegration...
All rocks and soils consist of minerals that have a distinctive scratch hardness. To define this ... more All rocks and soils consist of minerals that have a distinctive scratch hardness. To define this hardness, the Moh's hardness scale is the standard reference used. The scale is divided into 10 increments, ranging from talc (with a hardness of 1) as the softest, up to diamond (hardness 10) as the hardest. The scale is naturally linear from a hardness of 1 to 9, with each mineral being able to scratch the one below it in the scale. Among the most common minerals, mica and calcite are very soft (hardness 2.5 and 3, respectively), while feldspar, pyroxene and amphibole may be characterised as medium hard (hardness 6). Quartz and garnet are very hard (hardness 7 and 7-7.5, respectively), and to a great extent, determine the degree of TBM cutter wear. Cutter life can be estimated from the relative percentage of minerals of different Moh's hardness classes (>7, 6-7, 4-5 and <4). For coarse-grained rock and soil this is most commonly determined by petrographic analysis using a...
TBM excavation has become increasingly common, despite the fact that precise evaluation of certai... more 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...
Tunnelling and Underground Space Technology, 2012
The demand for representative rock property parameters related to planning of underground excavat... more The demand for representative rock property parameters related to planning of underground excavations is increasing, as these parameters constitute fundamental input for obtaining the most reliable cost and time estimates. The Brittleness Value (S20), Sievers’ J-Value (SJ), Abrasion Value (AV) and Abrasion Value Cutter Steel (AVS) have been used extensively at NTNU/SINTEF since the 1960s in connection with drillability testing
Tunnelling and Underground Space Technology, 2013
Rock Mechanics and Rock Engineering, 2013
ABSTRACT The Cerchar abrasion index is commonly used to represent rock abrasion for estimation of... more ABSTRACT The Cerchar abrasion index is commonly used to represent rock abrasion for estimation of bit life and wear in various mining and tunneling applications. Although the test is simple and fast, there are some discrepancies in the test results related to the equipment used, condition of the rock surface, operator skills, and procedures used in conducting and measuring the wear surface. This paper focuses on the background of the test and examines the influence of various parameters on Cerchar testing including pin hardness, surface condition of specimens, petrographical and geomechanical properties, test speed, applied load, and method of measuring wear surface. Results of Cerchar tests on a set of rock specimens performed at different laboratories are presented to examine repeatability of the tests. In addition, the preliminary results of testing with a new device as a potential alternative testing system for rock abrasivity measurement are discussed.
Increased urbanisation constantly demands more infrastructure, often requiring the construction o... more 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...
ABSTRACT Tunnelling by use of Tunnel Boring Machine (TBM) is gaining a greater presence as a suit... more ABSTRACT Tunnelling by use of Tunnel Boring Machine (TBM) is gaining a greater presence as a suitable excavation method. Disc cutter consumption has a strong influence on performance and cost when using TBMs and the influence becomes even more relevant in hard rock. Furthermore, good predictions of TBM performance and cost facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory assessments are needed. A new abrasivity test method called Rolling Indentation Abrasion Test was developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than traditionally used methods by introducing wear by rolling contact on intact rock samples.
Tunnels and Tunnelling International, 2012
Increased urbanisation constantly demands more infrastructure, often requiring the construction o... more 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...
Weakness zones or faults containing swelling clay represent a challenging situation in hard rock ... more Weakness zones or faults containing swelling clay represent a challenging situation in hard rock tunnelling. When excavating in such zones, failures have occurred occasionally even though particular precautions have been taken. Instability has been encountered during tunnel excavation and sometimes also long after tunnel completion. One of the most recent cases of failure, the rock fall at the Hanekleiv road tunnel in southeast Norway, occurred ten years after tunnel completion. The rock fall was in a fault zone where swelling clay had been identified, about 1.1 km from the northern tunnel entrance of the southbound tube. Cracks had been detected in the applied shotcrete at the fault zone during tunnel excavation. In one major weakness zone containing swelling clay at the Finnfast subsea tunnel, monitoring was carried out by the Norwegian Geotechnical Institute (NGI). Strain gauges and load cells were installed in the reinforced shotcrete rib near the crown and at springlines of the...
Weaknesses zones consisting of sheared and fractured rock mass have a swelling potential in the p... more Weaknesses zones consisting of sheared and fractured rock mass have a swelling potential in the presence of clays rich in montmorillonite. When it comes to intact rocks there are questions regarding both the swelling potential and the main reasons for swelling in the different rock types. This is experienced in several projects, where swelling of intact rock has been different than what was expected. To better understand what is causing the behaviour of intact rock when exposed to water a comprehension on the water impact on the swelling potential is required. For clay minerals the swelling mechanisms and factors influencing on the swelling potential is explained and confirmed by comprehensive research. Four types of clay minerals are discussed to describe the swelling potential of these minerals in contact with water. The extensive laboratory work performed for this thesis addresses a study on the expansive character of intact rock. Three different rock types are tested; alum shale...
Rock Mechanics and Rock Engineering, 2015
The tunnel boring machine (TBM) method has become widely used and is currently an important prese... more The tunnel boring machine (TBM) method has become widely used and is currently an important presence within the tunnelling industry. Large investments and high geological risk are involved using TBMs, and disc cutter consumption has a great influence on performance and cost, especially in hard rock conditions. Furthermore, reliable cutter life assessments facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory tests for rock abrasivity assessments are needed. A new abrasivity test method by rolling disc named Rolling Indentation Abrasion Test (RIAT) has been developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than the traditionally used methods. Wear by rolling contact on intact rock samples is introduced and several rock types, covering a wide rock abrasiveness range, have been tested by RIAT. The RIAT procedure indicates a great ability of the testing method to assess abrasive wear on rolling discs. In addition and to evaluate the newly developed RIAT test method, a comprehensive laboratory testing programme including the most commonly used abrasivity test methods and the mineral composition were carried out. Relationships between the achieved results from conventional testing and RIAT results have been analysed.
Geotechnical Testing Journal
Tunnelling and Underground Space Technology
Tunnelling by use of Tunnel Boring Machine (TBM) is gaining a greater presence as a suitable exca... more Tunnelling by use of Tunnel Boring Machine (TBM) is gaining a greater presence as a suitable excavation method. Disc cutter consumption has a strong influence on performance and cost when using TBMs and the influence becomes even more relevant in hard rock. Furthermore, good predictions of TBM performance and cost facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory assessments are needed. A new abrasivity test method called Rolling Indentation Abrasion Test was developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than traditionally used methods by introducing wear by rolling contact on intact rock samples.
The new NTNU Soil Abrasion Test (SAT) is a further development of the existing abrasion tests for... more The new NTNU Soil Abrasion Test (SAT) is a further development of the existing abrasion tests for rock (Bruland et al. 1995). Compared with the AVS test (T&TI April, p48), only one detail has been changed: a sieved soil sample <1mm is used instead of crushed rock powder <1mm. Test procedure To enable comparison with previous test results, and to take advantage of the extensive NTNU database it is considered important to follow the standardised NTNU abrasion test procedures as closely as possible. The following preparation of soil samples is therefore recommended, and has been followed for the testing described: In order to reduce or avoid changes of the original properties, soil samples should be dried gently in a ventilated oven at 30˚C for 2-3 days. The following techniques should be used after drying in order to disintegrate and separate particles for the abrasion powder: 1) Disintegration by use of a soft hammer. 2) Sieving with steel balls as gentle milling/disintegration...
All rocks and soils consist of minerals that have a distinctive scratch hardness. To define this ... more All rocks and soils consist of minerals that have a distinctive scratch hardness. To define this hardness, the Moh's hardness scale is the standard reference used. The scale is divided into 10 increments, ranging from talc (with a hardness of 1) as the softest, up to diamond (hardness 10) as the hardest. The scale is naturally linear from a hardness of 1 to 9, with each mineral being able to scratch the one below it in the scale. Among the most common minerals, mica and calcite are very soft (hardness 2.5 and 3, respectively), while feldspar, pyroxene and amphibole may be characterised as medium hard (hardness 6). Quartz and garnet are very hard (hardness 7 and 7-7.5, respectively), and to a great extent, determine the degree of TBM cutter wear. Cutter life can be estimated from the relative percentage of minerals of different Moh's hardness classes (>7, 6-7, 4-5 and <4). For coarse-grained rock and soil this is most commonly determined by petrographic analysis using a...
TBM excavation has become increasingly common, despite the fact that precise evaluation of certai... more 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...
Tunnelling and Underground Space Technology, 2012
The demand for representative rock property parameters related to planning of underground excavat... more The demand for representative rock property parameters related to planning of underground excavations is increasing, as these parameters constitute fundamental input for obtaining the most reliable cost and time estimates. The Brittleness Value (S20), Sievers’ J-Value (SJ), Abrasion Value (AV) and Abrasion Value Cutter Steel (AVS) have been used extensively at NTNU/SINTEF since the 1960s in connection with drillability testing
Tunnelling and Underground Space Technology, 2013
Rock Mechanics and Rock Engineering, 2013
ABSTRACT The Cerchar abrasion index is commonly used to represent rock abrasion for estimation of... more ABSTRACT The Cerchar abrasion index is commonly used to represent rock abrasion for estimation of bit life and wear in various mining and tunneling applications. Although the test is simple and fast, there are some discrepancies in the test results related to the equipment used, condition of the rock surface, operator skills, and procedures used in conducting and measuring the wear surface. This paper focuses on the background of the test and examines the influence of various parameters on Cerchar testing including pin hardness, surface condition of specimens, petrographical and geomechanical properties, test speed, applied load, and method of measuring wear surface. Results of Cerchar tests on a set of rock specimens performed at different laboratories are presented to examine repeatability of the tests. In addition, the preliminary results of testing with a new device as a potential alternative testing system for rock abrasivity measurement are discussed.