Development of an Automatic Rock Mass Classification System Using Digital Tunnel Face Mapping

Quantitative granitic weathering assessment for rock mass classification optimization of tunnel face using image analysis technique

This paper presents a case study of a digital discontinuity mapping system used as a rock mass characterization tool in an underground hard rock mine. This mapping system allows for a fast acquisition of information that can best characterize the geological structural regime without exposing workers to potentially unsafe conditions. This method can be used to overcome some of the shortcomings of traditional mapping methods, such as limited access to rock exposures. Photographic images of the exposed rock mass are introduced into a software package that has been developed to extract potential discontinuity traces using detection algorithms. Detected features that do not describe discontinuity traces are removed from the images using artificial neural networks. Operator intervention can improve the reliability of the system by linking incomplete discontinuity segments. This developed process results in the construction of a discontinuity trace map that can be used for rock mass characterization purposes. The system was employed to construct discontinuity trace maps of twenty 1.8 m by 1.8 m mapping windows from two locations in an underground hard rock mine. The ability of the system to quantify the geomechanical characteristics of the rock mass was evaluated by comparing the results with those of manually drawn discontinuity trace maps. The results of this study have helped to evaluate the digital face mapping system and identify its limitations.Key words: rock mass characterization, image processing, discontinuity networks, neural networks.

The determination of representative elementary volume (REV) is critical for mechanical model establishment and the determination of rock mass mechanical properties. Therefore, in this study, the REV range, existence, determinate parameter, and category were discussed. The blockiness level of the rock mass (Bz) was defined as the new index to determine the geometrical rock mass REV. Then, a great variety of multiscale three-dimensional fractured network models with different discontinuity persistences and spacings were developed. Finally, the Bz values of all models were measured, and the geometrical REVs were determined, the correlation between the geometrical REVs and rock mass discontinuity properties were assessed, and size validations of geometrical REVs were performed. In this study, it is shown that the REV is approximately 20–50 times that of the discontinuity spacing when the discontinuity spacing is classified as having extremely close to close spacing and is between approximately 0.3 and 4.0 times the discontinuity diameter when discontinuity spacing is in the range from moderate to extremely wide spacing. Further, there is a fourth-order nonlinear correlation between the geometrical REV and the ratio of the discontinuity diameter to discontinuity spacing. Meanwhile, the validation results confirm that the geometrical REV is slightly less than the sizes at which the elastic moduli tend to plateau, and the rationality of the geometrical REV of a rock mass based on Bz is thus supported from another perspective.

The purpose of this paper is to present an Integrated Life Cycle Bridge Information Modeling that can be used throughout different phases of the bridge life cycle including: design, construction, and operation and maintenance phases. Bridge Information Modeling (BrIM) has become an effective tool in bridge engineering and construction. It has been used in obtaining accurate shop drawings, cost estimation, and visualization. In this paper, BrIM is used as an integrated tool for bridges life cycle information modeling. In the design phase, BrIM model can be used in obtaining optimum construction methods and performing structural advanced analysis. During construction phase, the model selects the appropriate locations for mobile cranes, monitors the status of precast components, and controls documents. Whereas, it acts as a tool for bridge management system in operation and maintenance phase. The paper provides a detailed description for each use of BrIM model in design, construction, and operation and maintenance phases of bridges. It is proven that BrIM is an effective tool for bridge management systems throughout their life phases.

A modified rock mass classification system for TBM tunnels and tunneling based on the HC method of China

Advanced stability analysis method for the tunnel face in jointed rock mass based on DFN-DEM

Mechanism analysis of tunnel collapse in a soft-hard interbedded surrounding rock mass: A case study of the Yangshan Tunnel in China

When the two excavation faces of a tunnel constructed from both the entrance and exit simultaneously in soft surrounding rock approach, the excavation surface disturbance areas are superimposed, stress and deformation in the surrounding rock become extraordinarily complex, which results in substantial deformation and instability. By combining the study of the surrounding rock stress and displacement caused by both unidirectional and face-to-face excavation in the Shizilong Tunnel, the stability of the tunnel face with two excavation faces approaching one another in a bidirectional construction is analyzed by numerical analysis. It is shown that, with the reduction in the length of the unexcavated soil between the two excavation faces, the plastic zone and deformation significantly increase, and the arching effect gradually weaken, resulting in greatly reduced tunnel stability. When the distance between the two excavation faces is less than the limiting distance, an extended range of the surrounding rock approaches plastic failure, and only effective countermeasures can guarantee the safety of the tunnel construction. Further, bamboo anchor pipe grouting is adopted to reinforce tunnel faces with the initial support strengthened, when those two excavation faces in the construction of the Shizilong Tunnel are approaching. Field implementation indicates that the tunnel is excavated safely.

With the wave of the Fourth Industrial Revolution, the construction industry is also witnessing the application of numerous state-of-the-art technologies. Among these, augmented reality (AR) technology has the advantage of utilizing existing 3D models and BIM data and is thus an area of active research. However, the main area of research to date has either been in visualizing information during the design phase, where architects and project stakeholders can share viewings, or in confirming the required information for construction management through visualization during the construction phase. As such, more research is required in the application of AR during the facility management (FM) phase. Research utilizing BIM in the FM phase, which constitutes the longest period during the lifecycle of a building, has been continuously carried out but has faced challenges with regard to on-site application. The reason for this is that information required for BIM during the design, construction and FM phases is different, and the reproduced information is vast, so identifying the required BIM data for FM and interfacing with other systems is difficult. As a measure to overcome this limitation, advanced countries such as the US and UK have developed and are using Construction Operations Building information exchange (COBie), which is an open-source BIM-based information exchange system. In order to effectively convert open-source BIM data to AR data, this research defined COBie data for windows and doors, converted them to a system and validated that it could actually be applied for on-site FM. The results of this system’s creation and validation showed that the proposed AR-based smart FMS demonstrated faster and easier access to information compared with existing 2D blueprint-based FM work, while information obtained through AR allowed for immediate, more visual and easier means to express the information when integrated with actual objects.

During the construction of tunnel, the observational classification of rock mass quality is the most direct method to evaluate the quality of the tunnel face surrounding rock. It is also an important basis for preventing geological disasters in tunnel construction, deciding construction excavation method and supporting measures. The traditional Q method and BQ method of national standard rock mass quality grading evaluation method require on-site and indoor laboratory tests and analysis, which results in the lag time of rock mass quality evaluation, often reduces the construction efficiency, or misses the window time to prevent sudden construction geological disasters. Rapidly and accurately to rock mass quality classification of tunnel face is the primary problem to be solved in observational rock mass classification of highway tunnel during construction period. The artificial intelligence algorithm provides a method to solve the real-time and accurate evaluation of the rock mass of the tunnel. Taking Yanqing-Chongli highway for Beijing Winter Olympic Games as an example, we adopt a method of using photogrammetry and artificial intelligence rock structure parameter to identify working face. In this method, seven index parameters system are established. We use the KNN intelligent algorithm to evaluate the quality of the tunnel rock and select 150 samples from 40 working faces in 8 tunnels for the training and learning. Another 50 samples are selected for rock mass quality evaluation and verification. Compared with the rock mass quality evaluation results of BQ, the accuracy reachs 90%. Conclusions are as follows. (1)KNN method for observational classification of rock mass quality of highway tunnel is a fast and efficient method for observational classification of rock mass quality by using artificial intelligence technology, which can obtain real-time rock mass evaluation results on site. (2)KNN classification method selects seven discriminant indicators, considering the occurrence of rock environment, geological structure, rock structure and other characteristics, and reflecting the operability and applicability of these indicators in the actual engineering. (3)KNN classification method misjudgment rate is very low. It has strong discriminant ability when marking discriminant classification by excluding the influence of artificial factors. This method provides a new way to solve the rock mass grade determination and classification.

Purpose This paper aims to analyze the impact of sustainability measures taken during the design and construction phases, by examining two categories of sustainability: energy efficiency and reducing carbon emissions and material selection and waste management. These aspects are examined from the perspectives of long-term building performance and maintenance practices, as well as user/tenant satisfaction. Design/methodology/approach This study includes a literature review related to the two topics under consideration, followed by a comparative case study analysis of four projects to determine practical validity. All case studies in this paper used a semi-structured survey with various project stakeholders, which helped the authors identify measures taken as well as obstacles and challenges during the process. Findings According to the four case studies, adequate attention should be paid to the two areas of interest during a project’s design and construction phases. Including case studies from around the world (four case studies from three different countries) offers insights into effective sustainability practices in building design and construction, providing instances of successful implementation and emphasizing the obstacles and potential when incorporating sustainability into the design and construction phases. Research limitations/implications The findings also show that design and construction participants and companies should reduce waste generation and carbon emissions. In addition, they should make decisions on material selection to enhance projects’ sustainability and to contribute to creating a habitable planet for the future. Originality/value The influence of the design and construction phases on long-term project sustainability is of major importance and concern to users, owners, designers, contractors and facility managers. This study illustrates the necessity of including sustainability measures in the design and construction phases, highlighting the importance of sustainability in building design and construction through effective implementation techniques and interdisciplinary teamwork to realize sustainable goals.

The fragmented nature of the construction industry, lack of supervision on the operational status of buildings after completion and complexity of scoring systems of some sustainability assessment tools are among the reasons that make the implementation of such tools in developing countries difficult. The aim of this paper is to introduce a new criteria-based sustainability assessment tool for residential buildings in Iran by considering the project management body of knowledge as a reference for developing categories and a guideline to define a framework for evaluating different phases of construction. The analytic hierarchy process is employed as a method of prioritisation of the sustainability criteria studied. All the criteria are categorised into five groups: resource management, quality management, environmental impacts management, zone management and risk management, in which they are assessed in the three phases of design, construction and operation. The unique features of the tool that distinguish this tool from others are: assigning the project manager as the sole authority to implement, monitor and control the sustainable assessment tool; simplicity of assessment method; cyclic evaluation of project after completion; incorporating a managerial approach towards solving the environmental problems; and phasic appraisal of construction works.

Study on the tunneling response of TBM in stressed granite rock mass in Yinhan Water Conveyance tunnel

A displacement-based back-analysis method for rock mass modulus and horizontal in situ stress in tunneling – Illustrated with a case study

Rock slopes stability is important for personnel and equipment safety in the open-pit mine. Instability and failure of slope occur due to many factors such as unsuited slope geometry, geological discontinuities, weak slope material due to weather influences. External loads such as high rainfall and seismicity could play an essential role in slope failure. Consequently, a precise classification of rock mass is needed for the basis of determining technical policy. Rock slopes in open pit coal mining areas, especially in Indonesia, are characterized by applying various rock mass classification systems, such as Rock Mass Rating (RMR) and Geological Strength Index (GSI), because the study area comprises well-exposed rock formations. In the RMR system, there are five main parameters i.e. Rock Quality Designation (RQD), Uniaxial Compressive Strength (UCS) of rocks, discontinuity spacing, discontinuity and groundwater conditions were considered. Several rock mass classification systems developed for the assessment of rock slope stability were evaluated with the condition of rock slopes in the tropics, especially Indonesian region, particularly in sedimentary rocks in the open pit coal mining area in order to get the corrected GSI equation used to characterize rock slopes based on rock mass structure quantitative analysis and discontinuities surface conditions. This paper provides correlation between the GSI and RMR for sediment rock in coal mines.