Risk analysis and countermeasures of TBM tunnelling over the operational tunnel

To study the risk and control countermeasures of the TBM tunnel construction adjacent to the operational railway tunnel, based on the TBM tunnel project of Chongqing Rail Transit Line 5, this paper first evaluates the quality health degree of the operational tunnel lining (OTL) structure according to the on-site structural inspection. Then, the displacement, internal force, and proximity influence scope influenced by the metro TBM tunnel construction are studied using numerical simulation. Finally, the corresponding control countermeasures are proposed. The results show that: (1) The adjacent construction of the upper TBM tunnel will lead to the uplift deformation trend of the lower operational tunnel, and the uplift deformation of the vault is greater than that of the ballast bed. The influence scope is roughly a parallelogram, with the long axis parallel to the operational tunnel and the short axis parallel to the new TBM subway tunnel. (2) TBM tunnelling over the operational tunnel will cause the transformation of the mechanical mode of the OTL structure from the small eccentric compression mode to the large eccentric compression mode. The OTL structure between the left and right lines of TBM is unfavorable. (3) The longitudinal curve of the bending moment and axial force of the OTL fluctuates greatly within the influence range. The bending moment and axial force are reduced in operational tunnel construction joints. Based on field evaluation and numerical analysis, this paper puts forward some risk control countermeasures, such as TBM tunnelling parameters control, pea-gravel backfilling, backfill grouting, and bottom grouting, which can effectively solve the risk of the operational tunnel structure in the adjacent construction. This study has important reference value for risk control and safety assessment of tunnel in complex adjacent tunnel construction

Advances in Design Methodology in Swelling Shale Rock in Southern Ontario

As infrastructure requirements increase in southern Ontario, excavations within swelling rock formations will become more frequent and larger. The objective of this study is to advance design capability for structures in swelling rock through three aspects: i) developing a practical swelling model for design engineers, ii) investigate two crushable/compressible materials for the mitigation of swelling rock effects, and iii) observe and analyze the behaviour of swelling rock to current excavation techniques. A swelling rock constitutive model has been developed. The swelling parameters include the horizontal and vertical free swell potential, threshold stress, and critical stress as well as a “pseudo-Poisson’s ratio” effect that allows the practicing engineer to explore the interaction between orthogonal suppression pressures without the need for advanced testing. The model has been verified through analysis of swell tests and well-documented case studies. Extruded polystyrene foams and light-weight cellular grouts were tested at monotonic low strain rates mimicking the loading behaviour of swelling rock to identify their potential as mitigation materials. Results show low strain rates affect the yield strengths and elastic moduli. Cellular grout test results indicate it behaves as three-phase material in stress and groundwater conditions typical for infrastructure projects. Two case studies were investigated, monitoring, and analyzed. The Zone 1 Water Main project was located in the Halton Region, Ontario and the Billy Bishop Pedestrian Tunnel was located in Toronto, Ontario Results were analyzed to investigate the effect of excavation technique and shape on the elastic and time-dependent deformations of the rock mass

Proceedings of the 8th International Conference on Civil Engineering

This open access book is a collection of accepted papers from the 8th International Conference on Civil Engineering (ICCE2021). Researchers and engineers have discussed and presented around three major topics, i.e., construction and structural mechanics, building materials, and transportation and traffic. The content provide new ideas and practical experiences for both scientists and professionals

Advanced Underground Space Technology

The recent development of underground space technology makes underground space a potential and feasible solution to climate change, energy shortages, the growing population, and the demands on urban space. Advances in material science, information technology, and computer science incorporating traditional geotechnical engineering have been extensively applied to sustainable and resilient underground space applications. The aim of this Special Issue, entitled “Advanced Underground Space Technology”, is to gather original fundamental and applied research related to the design, construction, and maintenance of underground space

Proceedings of the 8th International Conference on Civil Engineering

This open access book is a collection of accepted papers from the 8th International Conference on Civil Engineering (ICCE2021). Researchers and engineers have discussed and presented around three major topics, i.e., construction and structural mechanics, building materials, and transportation and traffic. The content provide new ideas and practical experiences for both scientists and professionals

Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields

Innovations in Road, Railway and Airfield Bearing Capacity – Volume 2 comprises the second part of contributions to the 11th International Conference on Bearing Capacity of Roads, Railways and Airfields (2022). In anticipation of the event, it unveils state-of-the-art information and research on the latest policies, traffic loading measurements, in-situ measurements and condition surveys, functional testing, deflection measurement evaluation, structural performance prediction for pavements and tracks, new construction and rehabilitation design systems, frost affected areas, drainage and environmental effects, reinforcement, traditional and recycled materials, full scale testing and on case histories of road, railways and airfields. This edited work is intended for a global audience of road, railway and airfield engineers, researchers and consultants, as well as building and maintenance companies looking to further upgrade their practices in the field

Geotechnical Engineering for the Preservation of Monuments and Historic Sites III

The conservation of monuments and historic sites is one of the most challenging problems facing modern civilization. It involves, in inextricable patterns, factors belonging to different fields (cultural, humanistic, social, technical, economical, administrative) and the requirements of safety and use appear to be (or often are) in conflict with the respect of the integrity of the monuments. The complexity of the topic is such that a shared framework of reference is still lacking among art historians, architects, structural and geotechnical engineers. The complexity of the subject is such that a shared frame of reference is still lacking among art historians, architects, architectural and geotechnical engineers. And while there are exemplary cases of an integral approach to each building element with its static and architectural function, as a material witness to the culture and construction techniques of the original historical period, there are still examples of uncritical reliance on modern technology leading to the substitution from earlier structures to new ones, preserving only the iconic look of the original monument. Geotechnical Engineering for the Preservation of Monuments and Historic Sites III collects the contributions to the eponymous 3rd International ISSMGE TC301 Symposium (Naples, Italy, 22-24 June 2022). The papers cover a wide range of topics, which include: 　 - Principles of conservation, maintenance strategies, case histories - The knowledge: investigations and monitoring - Seismic risk, site effects, soil structure interaction - Effects of urban development and tunnelling on built heritage - Preservation of diffuse heritage: soil instability, subsidence, environmental damages The present volume aims at geotechnical engineers and academics involved in the preservation of monuments and historic sites worldwide

A comparative study on joints with and without gouge fill

Rock is a discontinuous medium and the discontinuity may be in the form of joints or faults. Hence, the strength of rock mass generally depends on the type of discontinuity present in the rock mass. The strength of jointed rock mass generally depends on the joint spacing, inclination parameter and the roughness parameter. This joint roughness is a vital parameter which generally governs the strength of the rock mass. The roughness is usually computed with the help of direct shear test (r = tanφj). The deformation characteristics of rock mass are another parameter which is usually taken care in addition to the strength of rock mass and can be computed with the help of uniaxial compressive strength test. As collection of jointed rock mass and field testing of rock mass is tedious as well as difficult, hence jointed rock mass models are generally made in the laboratory itself. In the present study, plaster of Paris was used for modeling laboratory specimens as it is locally available and at the same time casting of jointed rock mass specimen can be done easily. The joints in rock mass specimen were made at various angles of orientation (β0) which is varying from 00-900. These models were possessing joints with and without gouge fill. Clay was used as gouge material. Here, an attempt was made to compare the results of strength and deformation characteristics of jointed rock mass with and without gouge fill by using model material plaster of Paris. From the experiments it is found that for single jointed rock mass specimen without gouge fill at β= 300 strength was found to be 0.22 MPa which is minimum and at β= 900 strength was found to be 7.34 MPa which is maximum. For single jointed rock mass specimen with gouge , further trend of decrease in strength was found and this is due to decrease in roughness parameter.Here , also at β= 300 strength was found to be 0.11 MPa which is minimum and at β= 900 strength was found to be 6.79 MPa which is maximum. An empirical relationship σcr= e-0.008 x Jf is applicable for joints with gouge

Discrete element modelling of packed rock beds for thermal storage applications

Thesis (MScEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: The increased necessity to obtain power from other sources than conventional fossil fuels has led to the growing interest in solar power. The problem with the proposed technology is that it can only provide power during the day and therefore requires some sort of storage system, if power is to be supplied throughout the day and night. A number of storage systems exist, but the one of particular interest for this research, is packed rock beds. Rock beds have the advantage that if designed right, they have the potential to be one of the most cost effective means of storing thermal energy for solar power plants. Discrete Element Models (DEM) of rock beds were therefore developed through both experimental and numerical procedures, by conducting a series of sensitivity, calibration and verification studies. The developed models were then used to study various aspects associated with rock beds, which were either too impractical, impossible or too expensive to conduct through actual experimental work. This research focused specifically on the potential of constructing self-supporting tunnels within the rock beds in order to improve the air flow uniformity through the bed, while minimizing the pressure drop. It was observed that if the appropriate steps were followed, stable self-supporting tunnels could be formed. Valuable information such as the rock orientations resulting from different packing directions could also be derived from the models and finally, a method to convert the DEM models into the appropriate format such that it could be imported into a CFD preprocessor for future CFD studies, was developed.AFRIKAANSE OPSOMMING: Die verhoogde noodsaaklikheid om energie te verkry uit ander bronne as konvensionele fossielbrandstowwe, het gelei tot die groeiende belangstelling in sonkrag energie. Die probleem met die voorgestelde tegnologie is dat dit net energie gedurende die dag kan voorsien en dus word daar ’n stoorstelsel benodig indien energie deur beide die dag en nag voorsien moet word. Tans bestaan daar wel ’n aantal van hierdie stoorstelsels, maar die een wat van besondere belang is in hierdie navorsing, is verpakte klip beddens. Klip beddens het die voordeel dat, indien dit reg ontwerp is, dit oor die potensiaal beskik om een van die mees koste-doeltreffende middels te wees vir die stoor van termiese energie vir sonkragstasies. Diskreet Element Modelle (DEM) van die klip beddens is ontwikkel deur gebruik te maak van beide experimentele en numeriese metodes waartydens ’n reeks sensitiwiteits-, kalibrasie- en verifiëring studies uitgevoer is. Die ontwikkelde modelle is gebruik om verskeie aspekte van klip beddens te ondersoek, wat of te onprakties, onmoontlik of te duur is vanuit ’n eksperimentele oogpunt. Hierdie navorsing het spesifiek gefokus op die potensiaal om self-ondersteunende tonnels binne in die klip beddens te vorm, ten einde die egaligheid van die lugvloei deur die bed te verbeter, terwyl die drukval geminimeer word. Daar is waargeneem dat stabiele self-ondersteunende tonnels wel gevorm kon word indien die toepaslike stappe gevolg is. Waardevolle inligting soos die klip oriëntasies wat as gevolg van die verskillende verpakkings rigtings onstaan kon ook vanuit die model verkry word. Ten slotte is ’n metode ontwikkel om die DEM modelle na die toepaslike formaat te omskep sodat dit ten einde gebruik kan word in numeriese vloeidinamika studies

Engineering characteristics of rocks in Qatar; Applications on excavation and tunneling

Excavation as well as tunneling have become fundamental operations in the advanced civil engineering field. In Qatar, many subsurface construction operations take place in rocks. However, the lack of studies and research that analyze the subsurface rock components from a geotechnical engineering perspective has created unexpected construction conditions. Most of similar studies handled concerns about properties related to oil and gas fields. This research aims to provide a geotechnical study for rocks in Qatar, and to illustrate the impact of the existence of these rock layers on two civil applications; namely excavation and tunneling. During this study, soil investigation reports and rock samples are collected from several bores located in Qatar, and a classification system is utilized to classify the rock samples to identify and study the properties of the existed rocks. Also, numerous production rates from different tunneling and excavation projects are recorded and analyzed, in order to clarify the relation between these rates and the classified rock layers. Based on this analysis, a geotechnical study and mapping system for the rocks in Qatar are presented. Reliable tools for predicting the average productivities of excavation and tunneling projects in Qatar are developed, these tools are aiming to facilitate designing, bidding and executing processes involved with these types of rocks