Jet-grouting in underground construction

Author(s):  
P Malinin ◽  
A Malinin
Author(s):  
E. Yu. Kulikova

Construction processes and construction conditions are never repeated. Therefore, a method for improving environmental and technological reliability, which is applicable to the development of underground space, is necessary. Improving environmental and technological reliability in the development of the underground space of cities should be based on the reliability of the construction technologies. Systematization and analysis of world experience in the use of various combinations of construction technologies that increase the reliability of construction of underground facilities is an urgent scientific task, the solution of which allows increasing the efficiency of underground space development. Modern experience of underground construction expands the range of possibilities for improving the reliability of underground space development, based on the use of various underground construction technologies. Thus, the design of the head part of the tunneling boards is being improved, and the range of conditions for their use is increasing from inhomogeneous unstable soils to fragmented rock formations. The technology of micro - and mini-tunneling for laying pipelines for various purposes is becoming widespread. In almost any mining and geological conditions and at any depth, the new Austrian method of tunneling is used. Methods of soil strengthening aimed at reducing the risk of precipitation of the earth’s surface in urban conditions are being improved: chemical reinforcement, jet-grouting, etc. The role of monitoring of deformations and sedimentation of the earth’s surface in the area of underground object placement, its scientific support at all stages of the life cycle, and measures to minimize all types of risk is increasing.


Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 82
Author(s):  
Johanna Merisalu ◽  
Jonas Sundell ◽  
Lars Rosén

Construction below the ground surface and underneath the groundwater table is often associated with groundwater leakage and drawdowns in the surroundings which subsequently can result in a wide variety of risks. To avoid groundwater drawdown-associated damages, risk-reducing measures must often be implemented. Due to the hydrogeological system’s inherent variability and our incomplete knowledge of its conditions, the effects of risk-reducing measures cannot be fully known in advance and decisions must inevitably be made under uncertainty. When implementing risk-reducing measures there is always a trade-off between the measures’ benefits (reduced risk) and investment costs which needs to be balanced. In this paper, we present a framework for decision support on measures to mitigate hydrogeological risks in underground construction. The framework is developed in accordance with the guidelines from the International Standardization Organization (ISO) and comprises a full risk-management framework with focus on risk analysis and risk evaluation. Cost–benefit analysis (CBA) facilitates monetization of consequences and economic evaluation of risk mitigation. The framework includes probabilistic risk estimation of the entire cause–effect chain from groundwater leakage to the consequences of damage where expert elicitation is combined with data-driven and process-based methods, allowing for continuous updating when new knowledge is obtained.


Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 313
Author(s):  
Shinya Inazumi ◽  
Sudip Shakya ◽  
Takahiro Komaki ◽  
Yasuharu Nakanishi

This study focused on the middle-pressure jet grouting method, which has a complicated development mechanism for the columnar soil-improved body, with the aim of establishing a computer-aided engineering (CAE) system that can simulate the performance on a computer. Furthermore, in order to confirm the effect of middle-pressure jet grouting with mechanical agitation and mixing, a comparative analysis was performed with different jet pressures, the development situation was visualized, and the performance of this method was evaluated. The results of MPS-CAE as one of the CAE systems showed that the cement slurry jet ratio in the planned improvement range, including the periphery of the mixing blade, by the middle-pressure jet grouting together with the mechanical agitation and mixing was increased and a high quality columnar soil-improved body was obtained. It is expected that the introduction of CAE will contribute to the visualization of the ground, and that CAE will be an effective tool for the visual management of construction for ground improvement and the maintenance of improved grounds during the life cycle of the ground-improvement method.


2021 ◽  
Vol 11 (1) ◽  
pp. 744-754
Author(s):  
Marzena Lendo-Siwicka ◽  
Grzegorz Wrzesiński ◽  
Katarzyna Pawluk

Abstract Improper recognition of the subsoil is the most common cause of problems in the implementation of construction projects and construction facilities failures. Most often, their direct cause is the mismatch of the scope of geotechnical diagnosis to the appropriate geotechnical category, or substantive errors, including incomplete or incorrect interpretation in the creation of a geological-engineering model and often overlooked hydrogeological conditions. In many cases, insufficient recognition and documentation of geotechnical and/or geological and engineering conditions leads to damage and construction failures, delays in consider construction, and the increase of the investment budget. That’s why, in order to avoid the above, particular attention should be paid to proper geotechnical and geological-engineering documentation at the design and construction stages. The selected example of the investment analyzed errors in the geological-engineering documentation, which mainly concerned the lack of recognition of locally occurring organic soils, the incorrectly determined location of the groundwater table and the degree of compaction of non-cohesive soils, and numerous errors of calculated values of soil uplift pressure. The detection of the errors presented in the paper made it possible to select the correct technology for the construction of the sanitary sewage system and to increase the thickness of the horizontal shutter made of jet grouting columns in the area of the excavation. In addition, the article discusses the principles of proper calculation of limit states and subsoil testing, which have a significant impact on the implementation of planned investments.


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