摘要
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（K;）, 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 tunnel lining.The critical case of a pipe or tunnel in which the maximum tensile stress develops at its springline occurs when it is constructed at shallow depths in the QS layer. The results of the parametric study were used to suggest recommendations for the construction of tunnels in QS employing micro-tunneling.
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(K_o), 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 tunnel lining.The critical case of a pipe or tunnel in which the maximum tensile stress develops at its springline occurs when it is constructed at shallow depths in the QS layer. The results of the parametric study were used to suggest recommendations for the construction of tunnels in QS employing micro-tunneling.
基金
Ward and Burke Microtunneling Ltd. for its excellent technical and financial support
作者简介
Corresponding author.Dr.Hayder Mohammed Salim Al-Maamori is currently a post-doctoral fellow at the Department of Civil and Environmental Engineering at University of Western Ontario,London,ON,Canada.He was awarded the mitacs elevate post-doctoral fellowship immediately after he finished his PhD degree from the same university.This fellowship is industrial-related to resolve issues in the design and implementation methods in the industry and it is therefore highly competitive.Dr.Al-Maamori was awarded this fellowship for his excellent performance in resolving time-dependent effects of swelling rocks on microtunneling projects.He is expert in testing swelling rocks to derive their swelling and strength properties required in the design of underground structures.Dr.Al-Maamori developed a laboratory testing method to predict the swelling zone of the QS in the field.He has more than ten publications in different scientific journals and conference proceedings.Dr.Al-Maamori has over than 20 years of practical experience of civil and geotechnical engineering in the field at the Middle East region and Canada.This experience includes implementation,supervision and consulting of different projects,such as public buildings,infrastructures and airport construction,pipelines,water tanks,underground structures,horizontal and vertical drilling and micro-tunneling in shales,in addition to rock,soil and material testing.Dr.Al-Maamori is a member of the Professional Engineers of Ontario,the Canadian Geotechnical Society,and the Iraqi Engineer’s Union.E-mail address:halmaamo@uwo.ca(H.M.S.Al-Maamori).;Dr.M.Hesham El Naggar is a professor of Engineering at Western University,Canada.He is the Co-Editor-In-Chief of Soil Dynamics and Earthquake Engineering and Associate Editor of Canadian Geotechnical Journal.He published more than 400 technical papers/book chapters on foundations,soil-structure interaction,infrastructure and geotechnical earthquake engineering.He consulted on major projects worldwide involving power plants,petrochemical plants,cement plants and mining facilities as well as port and offshore structures.He received numerous awards including:Geosynthetics,Stermac,Meyerhof,Canadian Geotechnical Colloquium Speaker,Western Faculty Scholar,Outstanding Teaching,and Research Excellence Awards as well as the 2015 Ontario Professional Engineers Medal for Engineering Research&Development.He is an elected fellow of Engineering Institute of Canada and the American Society for Civil Engineers.;Dr.Silvana Micic is an adjunct professor in Department of Civil and Environmental Engineering of Western University,London,Canada.She is involved in specialized testing and the evaluation of swelling and strength properties of different rock formations.She is also involved in the research of strengthening soft clays using electrokinetics.To date,Dr.Micic has published over 20 papers in journals and conference proceedings.She was presented 8 awards including NSERC Industrial Research Fellowship,Ontario Graduate Scholarship and Dean’s Award for Research Excellence.Dr.Micic is also currently a Senior Geotechnical Engineer at EXP Services Inc.,Canadian Consulting Company.She has over 20 years’experience in geotechnical engineering practice,design and management including landslide,ground improvement,foundation,tunnel and road projects.Dr.Micic is a licenced engineer in Canada,Croatia and Bosnia-Herzegovina.She has an international experience working on various projects in Canada,USA,Bermuda,Bahamas,Guatemala,Qatar,Bosnia-Herzegovina and Croatia.Dr.Micic is a member of executive committee of Canadian Geotechnical Society and guest editor of Canadian Geotechnical Journal.
