Papers by Keyword: Underground Engineering

Abstract: The engineering practice shows that the application of grouting technology to treat underground engineering has strong applicability and is one of the most commonly used technical means at present. Based on the underground engineering, this paper introduces the research achievements of grouting materials in recent years, including cement-based grouting materials, mixed grouting materials, anti-scouring grouting materials, and ultra-fine cement grouting materials. Current demand of grouting materials in underground engineering, there exists large dosage of cement, high content, high cost, serious environmental pollution problems, such as looking for alternatives or mixed with other raw materials for preparation of cementation material become the development trend, compared with the cement grouting material, chemical grouting material with higher performance, but in smaller projects within the scope of application. How to reduce the production cost of chemical grouting materials, simplify the production process, overcome the existing toxicity, reduce environmental pollution and improve the durability of solidified body has become the bottleneck of its popularization and application. Some achievements have been made in the modification of cement or chemical materials by nanometer components, but there is still a long way to go before the large-scale application of grouting engineering.

Abstract: The stress and strain of surrounding rock and the development of plastic zone in the process of excavation of large underground cavern group have been the main concern of the design unit. The numerical simulation software is used to analyze the stability of caverns of an underground pumping station. The stress and displacement of the surrounding rock and the development of the plastic zone in the process of excavation are analyzed in detail. The results show that the tensile stress is easily generated in the side wall, and the maximum value can reach 4 M Pa. Correspondingly, the maximum displacement of the side wall part can reach 4 cm. The plastic zone is mainly concentrated in the surrounding rock near the side wall, the thickness can reach about 9 m. In general, the excavation of underground caverns is basically stable.

Abstract: Space-time effect of excavation damaged zone (EDZ) has great impact on identifying rock mass parameters in underground excavation engineering. In this paper, methods and models for simulating EDZ are reviewed and classified. Based on mechanism analysis, a practical model using radius-displacement-dependent deformation modulus is proposed for dynamic excavation feedback analysis. In the model, EDZ is viewed as a three dimensional heterogeneous and variable disturbing field of parameter during excavation process. Thus, deformation modulus of EDZ rock mass evolves with space-time change along with construction stages. The model is proved to be available in parameter identification for rapid feedback analysis of underground engineering.

Abstract: In order to obtain 3-D geological modeling and visualization of complicated underground engineering, a 3-D geological visualization modeling based on data structures of B-Rep and NURBS is proposed. Through comprehensive analysis of common data structure for describing the space topology in the field of computer graphics, rapid establishment of accurate topological relation of 3-D geological models for underground engineering in complicated geological conditions and cavern groups is achieved. And the high-quality geometrical data and topological relation information for the geological visualization of slope engineering are provided. By taking a large coal mine as an example, the 3-D visualization model with many functional applications based on geological information is given, which provides a basic platform for the realization of 3-D digital management.

Abstract: The article sums up post--disaster reconstruction of underground engineering. The post-disaster reconstruction of green concrete construction technology evaluation system was studie. Taking the underground engineering of administrative center of the Beichuan County as an example, the writer conducts a detailed analysis the post-disaster reconstruction underground engineering green concrete constution technology evaluation system research.

Abstract: Risk assessment is generally static. However, in the process of construction, there actually are plenty of changing variables; the result of the risk assessment should also change simultaneously. Real-time dynamic risk assessment is required to find problems and guide the construction at any time. It is hard for manual dynamic assessment because of the heavy workload to consider every changeable factor. Assistant computer system with automatic abnormal data tracking and risk assistant analysis is necessary. This paper will introduce the dynamic risk assessment function of this system.

Abstract: City underground engineering construction has the following characteristics: scattered construction sites, complex participants, massive data, delayed analysis of on-site information and early warning, limit range of risk evaluation and suggestion from experts, etc. in order to implement the safety and risk management system of Ji’nan underground engineering, improve the efficiency of safety monitoring and management, flatten the hierarchy of risk monitoring and management, there is an urgent need to establish the underground engineering safety and risk monitoring and management information system of Ji’nan. It will work as an important implement for Ji’nan’s underground engineering daily management and emergent decision-making.

Abstract: Many excavation and backfill methods can be used to construct a deep foundation pit, but foundation pit construction will undoubtedly affects security of existing metro station. This research based on a transfer station of Chengdu Metro, three-dimensional numerical simulation method was used to analyze the deformation of metro station by changing construction methods of foundation pit. The results show that: (1) Both excavation and backfill methods of foundation pit have a significant effect on connection segments of metro station. (2) The main body of metro station is largely unaffected by foundation pit construction but it has been in the process of subsidence. (3) The more the construction steps of foundation pit are, the more slowly the displacement of metro station changes. The above results certainly contribute to research and develop new types of construction methods for complicated metro station.

Abstract: In recent years, more and more attentions are paid to risk monitor and safety management technique due to the increasing underground engineering accidents. Compared to the rapid progress of underground engineering, the development of engineering risk management is backward. Engineering risk management has become a problem that must be solved in the first place to ensure construction safety. To solve this problem, a study was conducted on the safety issues encountered in Jinan underground engineering. In this paper, for the purpose of ensuring safety, reducing risk and controlling engineering quality, construction risk distribution disciplines were summed up while concept of safety and risk management was put forward.

Abstract: Based on many inquiries, analyses and researches, alternate measures of science and social science are taken in this paper, considering series of geo-environmental effect, and the harmfulness of geological effects in Chongqing main city are analysed. The basic counter measures and managing measures are suggested to treat geo-environmental problems in Chongqing main city so that a long-term plan of city-developing and the objective of a struggle based on real situation are set up. The analytic results are helpful to solve the serious geo-environmental effects, and push forward the study of urban geo-environmental problems of underground engineering in Chongqing.