EFFECT OF BLASTING ON THE STABILITY OF LINING DURING EXCAVATION OF NEW TUNNEL NEAR THE EXISTING TUNNEL

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working

DYNAMIC MODELING OF TUNNEL SURVEY SPATIOTEMPORAL DATA

Currently, for tunnels, the design centerline and design cross-section with timestamps are used for dynamic three-dimensional (3D) modeling. However, thisapproach cannot correctly reflect some qualities of tunneling or some special cases,such as landslips. Therefore, a dynamic 3D model of a tunnel based onspatiotemporal data from survey cross-sections is proposed in this paper. Thismodel can not only playback the excavation process but also reflect qualities of aproject typically missed. In this paper, a new conceptual model for dynamic 3Dmodeling of tunneling survey data is introduced. Some specific solutions areproposed using key corresponding technologies for coordinate transformation of cross-sections from linear engineering coordinates to global projection coordinates,data structure of files and database, and dynamic 3D modeling. A 3D tunnel TINmodel was proposed using the optimized minimum direction angle algorithm. Thelast section implements the construction of a survey data collection, acquisition, anddynamic simulation system, which verifies the feasibility and practicality of thismodeling method

Theory and Practice of Tunnel Engineering

Tunnel construction is expensive when compared to the construction of other engineering structures. As such, there is always the need to develop more sophisticated and effective methods of construction. There are many long and large tunnels with various purposes in the world, especially for highways, railways, water conveyance, and energy production. Tunnels can be designed effectively by means of two and three-dimensional numerical models. Ground–structure interaction is one of the significant factors acting on economic and safe design. This book presents recent data on tunnel engineering to improve the theory and practice of the construction of underground structures. It provides an overview of tunneling technology and includes chapters that address analytical and numerical methods for rock load estimation and design support systems and advances in measurement systems for underground structures. The book discusses the empirical, analytical, and numerical methods of tunneling practice worldwide

Hydraulic conductivity distribution in crystalline rocks, derived from inflows to tunnels and galleries in the Central Alps, Switzerland

Inflow data from 23 tunnels and galleries, 136km in length and located in the Aar and Gotthard massifs of the Swiss Alps, have been analyzed with the objective (1) to understand the 3-dimensional spatial distribution of groundwater flow in crystalline basement rocks, (2) to assess the dependency of tunnel inflow rate on depth, tectonic overprint, and lithology, and (3) to derive the distribution of fracture transmissivity and effective hydraulic conductivity at the 100-m scale. Brittle tectonic overprint is shown to be the principal parameter regulating inflow rate and dominates over depth and lithology. The highest early time inflow rate is 1,300l/s and has been reported from a shallow hydropower gallery intersecting a 200-m wide cataclastic fault zone. The derived lognormal transmissivity distribution is based on 1,361 tunnel intervals with a length of 100m. Such interval transmissivities range between 10−9 and 10−1m2/s within the first 200-400m of depth and between 10−9 and 10−4m2/s in the depth interval of 400-1,500m below ground surface. Outside brittle fault zones, a trend of decreasing transmissivity/hydraulic conductivity with increasing depth is observed for some schistous and gneissic geological units, whereas no trend is identified for the granitic unit

Application of geotechnical monitoring in tunnels with neural networks and finite elements methods

Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Σχεδιασμός και Κατασκευή Υπόγειων Έργων

General Report - Session 3

This General Report summarizes the 84 papers accepted for the Session 3 focused on: - 3a. Case Histories on Failure and Remediation of Slopes, Dams, Embankments and Landfills (53 papers), - 3b. Case Histories on Failure and Remediation of Retaining Structures, Slurry Walls, and Deep Excavations, Dewatering, Stability (27 papers), - 3c. Improving the Stability and Maintenance of Monuments (4 papers). The papers originate from 26 countries (11 European countries, 3 American countries, 11 Asian countries and 1 African country). The papers cover a number of relevant topics divided into three different sub - sessions. As for the two papers included in Session 3c, only one deals with maintenance and retrofit of historical monuments. Indeed paper 3.03c is more pertinent to session 3b. On the other hand some papers included in Session 3a could also be considered in Session 3b and vice versa

Tunnel Engineering

This volume presents a selection of chapters covering a wide range of tunneling engineering topics. The scope was to present reviews of established methods and new approaches in construction practice and in digital technology tools like building information modeling. The book is divided in four sections dealing with geological aspects of tunneling, analysis and design, new challenges in tunnel construction, and tunneling in the digital era. Topics from site investigation and rock mass failure mechanisms, analysis and design approaches, and innovations in tunnel construction through digital tools are covered in 10 chapters. The references provided will be useful for further reading

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

Geostructural stability assessment of cave using rock surface discontinuity extracted from terrestrial laser scanning point cloud

© 2018 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences The use of terrestrial laser scanning (TLS) in the caves has been growing drastically over the last decade. However, TLS application to cave stability assessment has not received much attention of researchers. This study attempted to utilize rock surface orientations obtained from TLS point cloud collected along cave passages to (1) investigate the influence of rock geostructure on cave passage development, and (2) assess cave stability by determining areas susceptible to different failure types. The TLS point cloud was divided into six parts (Entry hall, Chamber, Main hall, Shaft 1, Shaft 2 and Shaft 3), each representing different segments of the cave passages. Furthermore, the surface orientation information was extracted and grouped into surface discontinuity joint sets. The computed global mean and best–fit planes of the entire cave show that the outcrop dips 290° with a major north-south strike. But at individual level, the passages with dip angle between 26° and 80° are featured with dip direction of 75°–322°. Kinematic tests reveal the potential for various failure modes of rock slope. Our findings show that toppling is the dominant failure type accounting for high-risk rockfall in the cave, with probabilities of 75.26%, 43.07% and 24.82% in the Entry hall, Main hall and Shaft 2, respectively. Unlike Shaft 2 characterized by high risk of the three failure types (32.49%, 24.82% and 50%), the chamber and Shaft 3 passages are not suffering from slope failure. The results also show that the characteristics of rock geostructure considerably influence the development of the cave passages, and four sections of the cave are susceptible to different slope failure types, at varying degrees of risk

Railway freight transport and logistics: Methods for relief, algorithms for verification and proposals for the adjustment of tunnel inner surfaces

In Europe, the attention to efficiency and safety of international railway freight transport has grown in recent years and this has drawn attention to the importance of verifying the clearance between vehicle and lining, mostly when different and variable rolling stock types are expected. This work consists of defining an innovative methodology, with the objective of surveying the tunnel structures, verifying the clearance conditions, and designing a retrofitting work if necessary. The method provides for the use of laser scanner, thermocameras, and ground penetrating radar to survey the geometrical and structural conditions of the tunnel; an algorithm written by the authors permits to verify the clearances. Two different types of works are possible if the inner tunnel surfaces interfere with the profile of the rolling stock passing through: modification of the railroad track or modification of the tunnel intrados by mean milling of its lining. The presented case study demonstrates that the proposed methodology is useful for verifying compatibility between the design vehicle gauge and the existing tunnel intrados, and to investigate the chance to admit rolling stocks from different states. Consequently, the results give the railway management body a chance to perform appropriate measurements in those cases where the minimum clearance requirements are not achieved