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Research paper thumbnail of Wetting effects and strength degradation of swelling shale evaluated from multistage triaxial test

Underground Space, 2019

The multistage triaxial compression test was mainly utilized in this research to investigate the ... more The multistage triaxial compression test was mainly utilized in this research to investigate the degradation in the strength of swelling shale under different wetting conditions. Shale samples were tested in four different conditions: (1) under their natural moisture content denoted as intact, and after soaking in, (2) water, (3) polymer solution, and (4) bentonite solution, separately. The experimental results showed that a considerable decrease in the shale's strength was noted after soaking in water and the lubricant fluids (LFs). The polymer solution caused the least decrease in the strength compared to other fluids. Strength envelopes of the tested shale were constructed for intact and soaked states. These envelopes showed fair agreement between the single stage and the multistage triaxial compression test results, indicating suitability of the multistage triaxial compression test for the tested swelling shale.

Research paper thumbnail of Wetting effects and strength degradation of swelling shale evaluated from multistage triaxial test

Underground Space, 2019

The multistage triaxial compression test was mainly utilized in this research to investigate the ... more The multistage triaxial compression test was mainly utilized in this research to investigate the degradation in the strength of swelling shale under different wetting conditions. Shale samples were tested in four different conditions: (1) under their natural moisture content denoted as intact, and after soaking in, (2) water, (3) polymer solution, and (4) bentonite solution, separately. The experimental results showed that a considerable decrease in the shale's strength was noted after soaking in water and the lubricant fluids (LFs). The polymer solution caused the least decrease in the strength compared to other fluids. Strength envelopes of the tested shale were constructed for intact and soaked states. These envelopes showed fair agreement between the single stage and the multistage triaxial compression test results, indicating suitability of the multistage triaxial compression test for the tested swelling shale.

Research paper thumbnail of Influence of lubricant fluids on swelling behaviour of Queenston shale in southern Ontario

Canadian Geotechnical Journal, 2016

The feasibility of using the microtunnelling technique to install pipelines through Queenston sha... more The feasibility of using the microtunnelling technique to install pipelines through Queenston shale of southern Ontario is being investigated. In the microtunnelling technique, lubricant fluids — such as bentonite slurry and polymer solution — are used to facilitate excavation during installation of the pipeline sections. In this regard, a comprehensive testing program was performed to investigate the time-dependent deformation behaviour of Queenston shale considering lubricant fluids used in construction. The free swell test, semi-confined swell test, and the null swell test were utilized to perform this study. Results of 144 tests are presented and the variation of swelling characteristics of Queenston shale in lubricant fluids and in water is discussed briefly. The swelling model suggested by Lo and Hefny in 1996 was adopted to develop the swelling envelopes of Queenston shale in lubricant fluids and water in both horizontal and vertical directions with respect to the rock beddin...

Research paper thumbnail of A Compilation of the Geo-Mechanical Properties of Rocks in Southern Ontario and the Neighbouring Regions

Open Journal of Geology, 2014

The available measurements of the geo-mechanical properties of rocks in Southern Ontario and the ... more The available measurements of the geo-mechanical properties of rocks in Southern Ontario and the neighbouring regions (

Research paper thumbnail of Influence of water and lubricant fluids on peak strength of Queenston shale from southern Ontario

Canadian Geotechnical Journal, 2017

The strength of Milton Queenston shale (MQS) before and after soaking in water and lubricant flui... more The strength of Milton Queenston shale (MQS) before and after soaking in water and lubricant fluids (LFs) was examined. The investigated LFs (i.e., bentonite and polymer solutions) are utilized in the microtunnelling technique (MTT) to facilitate the installation of tunnel or pipe sections. To investigate the relevant mechanical properties of MQS under different wetting conditions, a series of laboratory tests including Brazilian split, uniaxial compression, and triaxial compression were carried out. These tests were performed on vertically and horizontally cored specimens with respect to the rock bedding. Fresh specimens (i.e., intact) and specimens soaked for 100 days in LFs and in water were examined. The 100 day period was selected, as it may reasonably represent the construction period where some swelling of the Queenston shale can occur. It was revealed that the strength of MQS substantially decreased after soaking. With greater impact in the vertical direction, both water and...

Research paper thumbnail of Swelling Potential of Queenston Shale in Lubricant Fluids

The effect of lubricant fluids used in the drilling process for microtunnels, such as polymers so... more The effect of lubricant fluids used in the drilling process for microtunnels, such as polymers solution and bentonite slurry, on the swelling behaviour of Quuenston Shale from Southern Ontario was investigated. Lubricant fluids and fresh water were used as ambient fluids in a series of free swell tests performed on Queenston shales from Niagara and Milton regions. The tests results revealed a significant difference in the swelling behaviour of the Queenston Shales in these fluids. The polymers solution caused a significant suppression of the swelling of both Queenston shales, while the bentonite slurry caused moderate suppression of the swelling of Niagara Queenston shale, and a slight increase of the swelling of Milton Queenston shale, compared to water. This finding may have a significant impact on evaluating the swelling associated with the drilling process and in the design of underground structures in Queenston Shale. RÉSUMÉ L'effet des fluides lubrifiants sur le comporteme...

Research paper thumbnail of Time-dependent behaviour of micro-tunneling construction in Queenston shale

The Queenston shale among other shales from southern Ontario exhibits timedependent deformation b... more The Queenston shale among other shales from southern Ontario exhibits timedependent deformation behaviour. This behaviour is manifested in the form of volume increase which can cause damage to the hosted underground structures. The time-dependent deformation of rocks can cause cracks in the springline of tunnels, wall inward movement, roof spalling and floor heave, which requires costly remedial measures. The expansion of the existing infrastructure in southern Ontario requires construction techniques, such as micro-tunneling to build new tunnels and pipelines under existing structures with minimal impact to these structures and to the environment. However, adopting this technique in swelling rocks, such as the Queenston shale requires an evaluation of its feasibility and functionality prior to its application. Accordingly, a comprehensive study that included experimental and numerical investigations was conducted to evaluate the impact of lubricant fluids used in micro-tunneling ap...

Research paper thumbnail of Numerical modeling of time-dependent deformation and induced stresses in concrete pipes constructed in Queenston shale using micro-tunneling technique

Effects of time-dependent deformation (TDD) on a tunnel constructed using the micro-tunneling tec... more Effects of time-dependent deformation (TDD) on a tunnel constructed using the micro-tunneling technique in Queenston shale (QS) are investigated employing the finite element method. The TDD and strength parameters of the QS were measured from tests conducted on QS specimens soaked in water and lubricant fluids (LFs) used in micro-tunneling such as bentonite and polymer solutions. The numerical model was verified using the results of TDD tests performed on QS samples, field measurements of some documented projects, and the closed-form solutions to circular tunnels in swelling rock. The verified model was then employed to conduct a parametric study considering important micro-tunneling design parameters, such as depth and diameter of the tunnel, in situ stress ratio (Ko), and the time lapse prior to replacing LFs with permanent cement grout around the tunnel. It was revealed that the time lapse plays a vital role in controlling deformations and associated stresses developed in the tun...

Research paper thumbnail of Performance of Vertical Shafts Constructed In Swelling Shale Using Finite Element Method

Micro-tunneling technique is employed to construct pipelines and tunnels in different types of gr... more Micro-tunneling technique is employed to construct pipelines and tunnels in different types of ground including swelling shales. However, these shales exhibit time-dependent deformation behavior, generally known as rock swelling that causes internal stresses in the underground structures in addition to those caused by the in-situ stresses. These combined stresses may exceed the allowable tensile or compressive strength of the concrete forming the pipeline, the tunnel liner and the walls of vertical shafts, which may result in cracks in these structures. Vertical shafts are used to initiate construction in micro-tunneling technique, then they are utilized as manholes for inspection and monitoring purposes of the constructed pipeline or tunnel. This paper investigates the induced stresses in vertical shafts caused by the timedependent deformations of swelling shales from south-western Ontario region. The induced stresses in vertical shafts are calculated numerically using the finite e...

Research paper thumbnail of Depth of Penetration of Lubricant Fluids and Water in Queenston Shale of Southern Ontario

Canadian Geotechnical Journal, 2016

Queenston shale is a rock formation located in southern Ontario in Canada that exhibits time-depe... more Queenston shale is a rock formation located in southern Ontario in Canada that exhibits time-dependent deformation behaviour induced by water penetration. Microtunnelling is an efficient technique that can be used to construct pipelines and tunnels in Queenston shale. In this technique, lubricant fluids, such as bentonite solution and polymer solution, are utilized, which can have a significant impact on the time-dependant deformation (i.e., swelling) of Queenston shale within their depth of influence. A test procedure was developed in this research to investigate the depth of penetration of lubricant fluids and water in Queenston shale. These fluids were applied under pressure, similar to that used in the microtunnelling process, on Queeenston shale specimens. The depth of penetration of these fluids into the test specimens was monitored with time. It was concluded that the penetration depth varied for the various fluids considered. Water had the deepest penetration into Queenston ...

Research paper thumbnail of Wetting effects and strength degradation of swelling shale evaluated from multistage triaxial test

Underground Space, 2019

The multistage triaxial compression test was mainly utilized in this research to investigate the ... more The multistage triaxial compression test was mainly utilized in this research to investigate the degradation in the strength of swelling shale under different wetting conditions. Shale samples were tested in four different conditions: (1) under their natural moisture content denoted as intact, and after soaking in, (2) water, (3) polymer solution, and (4) bentonite solution, separately. The experimental results showed that a considerable decrease in the shale's strength was noted after soaking in water and the lubricant fluids (LFs). The polymer solution caused the least decrease in the strength compared to other fluids. Strength envelopes of the tested shale were constructed for intact and soaked states. These envelopes showed fair agreement between the single stage and the multistage triaxial compression test results, indicating suitability of the multistage triaxial compression test for the tested swelling shale.

Research paper thumbnail of Wetting effects and strength degradation of swelling shale evaluated from multistage triaxial test

Underground Space, 2019

The multistage triaxial compression test was mainly utilized in this research to investigate the ... more The multistage triaxial compression test was mainly utilized in this research to investigate the degradation in the strength of swelling shale under different wetting conditions. Shale samples were tested in four different conditions: (1) under their natural moisture content denoted as intact, and after soaking in, (2) water, (3) polymer solution, and (4) bentonite solution, separately. The experimental results showed that a considerable decrease in the shale's strength was noted after soaking in water and the lubricant fluids (LFs). The polymer solution caused the least decrease in the strength compared to other fluids. Strength envelopes of the tested shale were constructed for intact and soaked states. These envelopes showed fair agreement between the single stage and the multistage triaxial compression test results, indicating suitability of the multistage triaxial compression test for the tested swelling shale.

Research paper thumbnail of Influence of lubricant fluids on swelling behaviour of Queenston shale in southern Ontario

Canadian Geotechnical Journal, 2016

The feasibility of using the microtunnelling technique to install pipelines through Queenston sha... more The feasibility of using the microtunnelling technique to install pipelines through Queenston shale of southern Ontario is being investigated. In the microtunnelling technique, lubricant fluids — such as bentonite slurry and polymer solution — are used to facilitate excavation during installation of the pipeline sections. In this regard, a comprehensive testing program was performed to investigate the time-dependent deformation behaviour of Queenston shale considering lubricant fluids used in construction. The free swell test, semi-confined swell test, and the null swell test were utilized to perform this study. Results of 144 tests are presented and the variation of swelling characteristics of Queenston shale in lubricant fluids and in water is discussed briefly. The swelling model suggested by Lo and Hefny in 1996 was adopted to develop the swelling envelopes of Queenston shale in lubricant fluids and water in both horizontal and vertical directions with respect to the rock beddin...

Research paper thumbnail of A Compilation of the Geo-Mechanical Properties of Rocks in Southern Ontario and the Neighbouring Regions

Open Journal of Geology, 2014

The available measurements of the geo-mechanical properties of rocks in Southern Ontario and the ... more The available measurements of the geo-mechanical properties of rocks in Southern Ontario and the neighbouring regions (

Research paper thumbnail of Influence of water and lubricant fluids on peak strength of Queenston shale from southern Ontario

Canadian Geotechnical Journal, 2017

The strength of Milton Queenston shale (MQS) before and after soaking in water and lubricant flui... more The strength of Milton Queenston shale (MQS) before and after soaking in water and lubricant fluids (LFs) was examined. The investigated LFs (i.e., bentonite and polymer solutions) are utilized in the microtunnelling technique (MTT) to facilitate the installation of tunnel or pipe sections. To investigate the relevant mechanical properties of MQS under different wetting conditions, a series of laboratory tests including Brazilian split, uniaxial compression, and triaxial compression were carried out. These tests were performed on vertically and horizontally cored specimens with respect to the rock bedding. Fresh specimens (i.e., intact) and specimens soaked for 100 days in LFs and in water were examined. The 100 day period was selected, as it may reasonably represent the construction period where some swelling of the Queenston shale can occur. It was revealed that the strength of MQS substantially decreased after soaking. With greater impact in the vertical direction, both water and...

Research paper thumbnail of Swelling Potential of Queenston Shale in Lubricant Fluids

The effect of lubricant fluids used in the drilling process for microtunnels, such as polymers so... more The effect of lubricant fluids used in the drilling process for microtunnels, such as polymers solution and bentonite slurry, on the swelling behaviour of Quuenston Shale from Southern Ontario was investigated. Lubricant fluids and fresh water were used as ambient fluids in a series of free swell tests performed on Queenston shales from Niagara and Milton regions. The tests results revealed a significant difference in the swelling behaviour of the Queenston Shales in these fluids. The polymers solution caused a significant suppression of the swelling of both Queenston shales, while the bentonite slurry caused moderate suppression of the swelling of Niagara Queenston shale, and a slight increase of the swelling of Milton Queenston shale, compared to water. This finding may have a significant impact on evaluating the swelling associated with the drilling process and in the design of underground structures in Queenston Shale. RÉSUMÉ L'effet des fluides lubrifiants sur le comporteme...

Research paper thumbnail of Time-dependent behaviour of micro-tunneling construction in Queenston shale

The Queenston shale among other shales from southern Ontario exhibits timedependent deformation b... more The Queenston shale among other shales from southern Ontario exhibits timedependent deformation behaviour. This behaviour is manifested in the form of volume increase which can cause damage to the hosted underground structures. The time-dependent deformation of rocks can cause cracks in the springline of tunnels, wall inward movement, roof spalling and floor heave, which requires costly remedial measures. The expansion of the existing infrastructure in southern Ontario requires construction techniques, such as micro-tunneling to build new tunnels and pipelines under existing structures with minimal impact to these structures and to the environment. However, adopting this technique in swelling rocks, such as the Queenston shale requires an evaluation of its feasibility and functionality prior to its application. Accordingly, a comprehensive study that included experimental and numerical investigations was conducted to evaluate the impact of lubricant fluids used in micro-tunneling ap...

Research paper thumbnail of Numerical modeling of time-dependent deformation and induced stresses in concrete pipes constructed in Queenston shale using micro-tunneling technique

Effects of time-dependent deformation (TDD) on a tunnel constructed using the micro-tunneling tec... more Effects of time-dependent deformation (TDD) on a tunnel constructed using the micro-tunneling technique in Queenston shale (QS) are investigated employing the finite element method. The TDD and strength parameters of the QS were measured from tests conducted on QS specimens soaked in water and lubricant fluids (LFs) used in micro-tunneling such as bentonite and polymer solutions. The numerical model was verified using the results of TDD tests performed on QS samples, field measurements of some documented projects, and the closed-form solutions to circular tunnels in swelling rock. The verified model was then employed to conduct a parametric study considering important micro-tunneling design parameters, such as depth and diameter of the tunnel, in situ stress ratio (Ko), and the time lapse prior to replacing LFs with permanent cement grout around the tunnel. It was revealed that the time lapse plays a vital role in controlling deformations and associated stresses developed in the tun...

Research paper thumbnail of Performance of Vertical Shafts Constructed In Swelling Shale Using Finite Element Method

Micro-tunneling technique is employed to construct pipelines and tunnels in different types of gr... more Micro-tunneling technique is employed to construct pipelines and tunnels in different types of ground including swelling shales. However, these shales exhibit time-dependent deformation behavior, generally known as rock swelling that causes internal stresses in the underground structures in addition to those caused by the in-situ stresses. These combined stresses may exceed the allowable tensile or compressive strength of the concrete forming the pipeline, the tunnel liner and the walls of vertical shafts, which may result in cracks in these structures. Vertical shafts are used to initiate construction in micro-tunneling technique, then they are utilized as manholes for inspection and monitoring purposes of the constructed pipeline or tunnel. This paper investigates the induced stresses in vertical shafts caused by the timedependent deformations of swelling shales from south-western Ontario region. The induced stresses in vertical shafts are calculated numerically using the finite e...

Research paper thumbnail of Depth of Penetration of Lubricant Fluids and Water in Queenston Shale of Southern Ontario

Canadian Geotechnical Journal, 2016

Queenston shale is a rock formation located in southern Ontario in Canada that exhibits time-depe... more Queenston shale is a rock formation located in southern Ontario in Canada that exhibits time-dependent deformation behaviour induced by water penetration. Microtunnelling is an efficient technique that can be used to construct pipelines and tunnels in Queenston shale. In this technique, lubricant fluids, such as bentonite solution and polymer solution, are utilized, which can have a significant impact on the time-dependant deformation (i.e., swelling) of Queenston shale within their depth of influence. A test procedure was developed in this research to investigate the depth of penetration of lubricant fluids and water in Queenston shale. These fluids were applied under pressure, similar to that used in the microtunnelling process, on Queeenston shale specimens. The depth of penetration of these fluids into the test specimens was monitored with time. It was concluded that the penetration depth varied for the various fluids considered. Water had the deepest penetration into Queenston ...