Grouting Technology Research Articles

Discussion on the Application of Grouting in Underground Engineering

With the development of China's economy, in some large cities, surface transportation alone can no longer meet people's needs today, and the development of underground engineering is increasingly catering to the needs of the public. During the excavation process of subway tunnels, it is inevitable that they may be threatened by groundwater, and grouting technology is one of the effective methods for preventing and controlling water in underground engineering. The mechanism of slurry flow and diffusion varies depending on the soil conditions. When underground projects such as subway tunnels pass through poor geological conditions, it is highly likely to cause significant surface subsidence, and even engineering disasters such as water inrush and collapse may occur. To ensure the safety of underground engineering construction in the geological strata, it is often necessary to carry out advanced grouting in the strata to achieve the purpose of reinforcement or water blocking. Advanced grouting reinforcement belongs to concealed engineering, and the existing advanced grouting construction mostly relies on experience and on-site grouting tests, making it difficult to achieve the expected grouting effect. Therefore, it is of great theoretical and engineering significance to conduct in-depth research on the diffusion mechanism of slurry in geological grouting reinforcement engineering, as well as the influence of factors such as slurry water cement ratio and geological characteristics on the diffusion form of slurry.

Research on energy-absorption active control method for large deformation of tunnel surrounding rock through multi-fault fracture zone

To study the problems of large deformation of surrounding rock and water-rich dense fracture zones during tunnel construction through fault fracture zone, the NPR (Negative Poisson’s Ratio) anchor cable control method is studied based on the Tabaiyi Tunnel. First, the mechanical deformation mechanism of surrounding rock is analyzed by geological conditions, lithology and strength of surrounding rock, and different surrounding rock zones are obtained. Then, based on the self-developed high-prestressed NPR anchor cable, the tunnel prevention and control measures are designed. The high-stress NPR anchor net technology is used to support the common large deformation and fault fracture zone, while in the water-rich dense fracture zones, the combined support of double gradient grouting technology and high-stress NPR anchor net technology is adopted. Finally, to evaluate the control effect of the support design scheme, the deformation of surrounding rock, the axial force of NPR anchor cable, and the pressure of steel arch are monitored in real time. The results show that the high-stress NPR anchor net technology can effectively control the large deformation of tunnel surrounding rock caused by fault zone. In addition, in the water-rich zones, the double gradient grouting technology can provide sufficient anchoring force for the NPR anchor cable. The two technologies control the maximum deformation of surrounding rock within 300 mm and realize the stability of tunnel primary support.

Numerical analysis and experimental study on slurry diffusion characteristics of vortical oscillatory grouting technology considering soil interface

Based on the fluidic jet theory, this study proposes an effective vortical oscillatory grouting technology. The fluid switching mechanism and pressure pulse characteristics are investigated through numerical simulation and experiment. The slurry diffusion performance of oscillatory grouting is compared with that of steady-pressure grouting under various soil parameters and slurry parameters. The effects of soil interface on diffusion behavior are also studied. The results show that the growth and dissipation of the vortex within the tool generate periodic oscillatory fluid, which further produces pressure pulses. During oscillatory grouting, the pressure recovery process inside the fluidic oscillator reduces the pressure of the soil. With the increase in porosity and particle size, the pressure of the soil grouted by oscillatory pressure is noticeably reduced. Despite the lower pressure of the soil, oscillatory grouting demonstrates better diffusion performance, owing to the dynamic flow field and pressure fluctuation. The performance of oscillatory grouting is also influenced by the oscillatory frequency and pressure pulse amplitude. When the soil interfaces are taken into consideration, different fluid domains exhibit complex slurry diffusion patterns. It is observed that the interface that is perpendicular to the grouting direction has a greater influence on grouting behavior. The oscillatory grouting diffusion behavior is more sensitive to the soil interface. This study is expected to improve grouting efficiency and promote the development of new grouting technology.

Diameter Measurement of Jet-Grouting Column Using Geo-Electrical Probe: Construction and Field Testing

Uncertainty about the geometry of jet grouting columns is a serious challenge to the efficiency of jet grouting technology. If this challenge can be met, jet grouting can become an efficient method of soil improvement. One proposed approach is measurement based on changes in the electrical resistivity between the column and surrounding soil. This approach is non-destructive, easy to use, fast and accurate. This paper reviews jet-grouting methods using the experimental research approach and reports on the design and construction of a probe equipped with ring electrodes that is suitable for measurement of the column diameter. The approach is based on the geoelectric method and Wenner theory. The probe was field tested on jet-grouting columns in a project in Bandar-e Gaz. The probe results were validated by visually observing the dimensions of the excavated column. The results showed that the probe performed well. The device measured a 90-cm column as being from 81 to 88 cm with an error of about 10%. The method of measuring the difference in electrical resistance was shown to be an accurate approach to solving the problem of uncertainty in the geometry of jet-grouting columns.

Assessing the results of work on strengthening the soils of the foundation of lock № 5 of the Volga-Don shipping canal and proposals for stabilizing the chamber position

The results of work to strengthen the soil foundation of the chamber of lock № 5 of the Volga-Don Shipping Canal, carried out in 2016–2017, are analyzed. The need to carry out work to strengthen the soil was caused by an increase in the intensity of sedimentation of the central sections of the lock chamber, which began in 2005. To stabilize the chamber position, the technology of two-component jet grouting is implemented. This technology assumes the formation of several longitudinal soil-cement walls in the soils of the lock chamber base, which would transfer the load from the weight of the chamber to the harder clay soils of the water-resistant layer. However, as a result of the work performed, the precipitation intensity has increased. Engineering-geological, hydrological and geophysical studies conducted in 2018–2020 recorded the absence of formed soil-cement elements in the soils of the chamber base. An analysis of the soil samples characteristics taken from the chamber base has showed that a layer of soils of 10–12 m thickness is composed of loess rocks, below which water-resistant clayey rocks lie. Initially, there were several confined and non-confined aquifers in the soils of the lock base, and the creation of a hydroelectric complex and the formation of a level difference between the upper and lower pools led to the formation of a filtration flow with a significant pressure gradient at the base of the chamber. An analysis of the properties and structure of loess soils has showed their predisposition to subsidence, transition to a floating state and liquefaction with an increase in water content. Under the conditions of weak water-saturated loess soils, the supply of a cement mixture into them under significant pressure did not lead to the formation of soil-cement elements. Thus, in accordance with the current regulatory documents, the technical condition of the gateway is defined as pre-emergency, and the security level is defined as unsatisfactory. Methods for reducing the intensity of the chamber sedimentation such as cutting through the loess layer with piles, physical and chemical strengthening of soils and water protection of the massif at the base of the chamber are considered and evaluated.

Identification and control of prestress loss of concrete members

Prestressing technology is widely used in buildings, Bridges and other infrastructures, but the problem of prestress loss has been a hinder for the use and maintenance of these facilities. so how to find the existence of prestress loss in time and accurately measure the existing effective prestress is a hot topic. This paper focuses on the development of prestress loss identification methods. They can be classified according to the technical route of direct measurement and indirect calculation. A large number of studies have shown that prestress loss often occurs in the construction stage of the structure. In order to better avoid the problems that may occur during this period, intelligent tensioning and grouting technology has been proposed and is constantly developing, serving various projects. By summarizing the advantages and disadvantages of existing studies, analysis of the means of prestress loss limitation can be formed, looking forward to peek the future development trend of intelligent control methods.

Infiltration Grouting Mechanism of Bingham Fluids in Porous Media with Different Particle Size Distributions

Although permeation grouting technology has been widely used in engineering practice, there has not been sufficient research on how the distribution of pore sizes in porous media affects the diffusion of grout. In this study, based on the fractal theory of porous media and the Bingham fluid rheological equation, a Bingham fluid permeation grouting mechanism considering the distribution of pore sizes in porous media is proposed. The mechanism is validated through laboratory experiments and numerical simulations using COMSOL 6.0. During the experiments, parallel electrical resistance imaging is employed to monitor the diffusion range of the grout. Furthermore, the effects of grouting pressure, porosity, and water–cement ratio on the diffusion radius of the grout are analyzed. The results show that the Bingham fluid grout diffuses in a semi-spherical shape in the gravel. Additionally, parallel electrical resistance imaging can analyze the diffusion range of the grout in the gravel. The diffusion radius of the Bingham fluid grout in the gravel is smaller than the diffusion radius obtained by considering the particle size distribution theory, with an average difference of 31.8%. Compared to the diffusion radius obtained without considering the particle size distribution theory, the diffusion radius obtained by considering the distribution of pore sizes is closer to the experimental results. The numerically simulated program, which was developed for this study, can effectively simulate the diffusion law of the Bingham fluid in the gravel. So far, the Bingham fluid seepage grouting model considering the different particle size distribution of porous media has been built. The findings of this study can provide theoretical support and technical reference for practical grouting projects.

Influence of rheological parameters on cement slurry penetration characteristics of novel oscillating grouting technology

Traditional grouting techniques are primarily based on stable-pressure grouting, with slurry penetration performance limited. Research on the penetration behavior of pulsating slurry is relatively scarce, with even less research focused on the influence of slurry rheological parameters.This paper proposes an efficient oscillating grouting technology (OGT) that can generate pressure pulses and periodically change the direction of slurry motion. Through experiments and numerical simulations, its working mechanism is investigated, and the penetration distance of oscillating grouting and steady pressure grouting is compared under different soil parameters (porosity and particle size). The effect of cement slurry rheological parameters (viscosity of the Newtonian fluid and the K, τ0 and n, of the Herschel-Bulkley fluid) on penetration distance, grouting pressure, pressure pulse amplitude, and oscillating frequency are studied. Finally, the correlation analysis between penetration behavior, oscillating parameters, and rheological parameters is conducted. The results show that the oscillatory switching of the slurry is related to the interaction of vortexes within the tool, and the switching process leads to the generation of pressure pulsations. Under different soil parameters and rheological parameters, the penetration distance of oscillating grouting is larger than that of steady-pressure grouting. Furthermore, due to the pressure recovery process within the oscillatory grouting tool, the oscillating grouting exerts less pressure on the soil, which can prevent soil fracturing. The results also indicate that the oscillatory grouting requires a certain level of flow resistance to achieve optimal effect, but excessive resistance can impede the slurry switching process and reduce the penetration distance. And the optimal values for K, τ0 and n are around 0.015 Pa·sn, 1.5 Pa, and 0.5, respectively. According to the correlation analysis, oscillating frequency is positively correlated with penetration distance. Average pressure and rheological parameters are negatively correlated with penetration distance.

Excavation and Construction Technology of Diversion Tunnel under Complex Geological Conditions

During the construction of a diversion tunnel, geological problems often include faults, fragile strata, hard rock formations, karst landforms, etc., which may have adverse effects on the excavation and construction of the diversion tunnel. Based on the analysis of the engineering overview, this study designed a new construction technology for the excavation of water diversion tunnels in hard rock layers and high-karst areas. Based on tunnel seismic prediction (TSP) technology to achieve advanced geological prediction, combined with actual geological conditions, construction difficulties are analyzed. Then, detection technology is used to collect two-way travel time, amplitude, and waveform data. By processing and analyzing the detection image, the spatial orientation and length of the main tunnel during the construction of the diversion tunnel are calculated. After completing the construction ventilation and wind, water, and electricity layout, the excavation construction procedure is designed. In the specific excavation design, the tunnel curtain excavation technology, tunnel body excavation and support technology, excavation grouting technology, important unfavorable geological tunnel section excavation technology, upper/lower flat section excavation technology, upper/lower curved section excavation technology, and vertical shaft section excavation technology were elaborated. Finally, a plan was made for the reuse process of slag material and a construction quality control system was established. During the testing process, it was found that the antidamage coefficient of the side wall was above 0.9 after using the technology described in this article. Therefore, it indicates that the excavation construction technology designed in this article can ensure the support capacity of the side wall of the diversion tunnel, which is suitable for the excavation of the main tunnel during the construction of the diversion tunnel.

A state-of-art review on development and progress of backfill grouting materials for shield tunneling

Backfill grouting plays a vital role in shield tunneling. This paper aims to present a comprehensive review of the development and progress of backfill grouting materials specifically designed for shield tunneling. Initially, the various components of grouts, such as pozzolanic materials, filling fine aggregates, and chemical additives, are introduced and discussed in detail. Subsequently, this study investigates critical properties including workability, mechanical properties, and durability of the grouts. Additionally, the principal factors influencing the properties are summarized, along with recommended ranges for specific geological conditions. Furthermore, the paper elucidates the diffusion mechanism of grouting mortars by presenting the current grouting models employed in shield tunneling. Recent advancements in grouting materials are extensively studied and extended, offering new perspectives for future grouting technology in shield tunneling. This study provides valuable insights into overcoming the existing challenges associated with shield tunnel grouting and promoting the evolution of current grouting materials.

The role of bentonite in two-component grout: A comparative study

Two-component grout is the most used backfilling technology in shielded mechanised tunnelling. Bentonite is an important ingredient in the production of component A, since it plays a key role in the mortar stabilisation. Furthermore, recent studies have highlighted its involvement in the mechanical and elastic performance of the hardened grout after short curing times, while no information is available for long curing times. This study proposes an innovative test campaign, based on a comparison between a standard two-component grout mix design (reproduced with 5 different bentonites) and a special mix design, produced without using the bentonite. This interesting comparison highlights the important role of the bentonite and its activation time in properties related to fresh grout (component A) and hardened grout. Assessments of bleeding, viscosity, unit weight, gel time, surface compression strength (SCS), uniaxial compression strength (UCS) and tensile strength (T0) have permitted a deep quantitative analysis that, undoubtedly, highlights the importance of bentonite in this widespread backfilling grout technology.

A study on carbon dioxide emissions of high-polymer road maintenance technology based on life cycle assessment evaluation

Road repair and maintenance is the foundation for maintaining the health of roads. High-polymer grouting technology is an advanced non-excavation road repair and reinforcement technique. However, there is limited existing research focusing on this material and technique's carbon dioxide emissions and influencing factors. This study aims to elucidate the carbon dioxide emissions in the life cycle assessment of high-polymer grouting repair technology, using the example of maintenance work on semi-rigid asphalt pavement. The solidification reaction of each kilogram of high-polymer grouting material will release approximately 11.82 g of carbon dioxide. Comparative analysis was conducted by juxtaposing the carbon dioxide emissions at various stages of high-polymer grouting technology with those of cement grouting techniques and traditional excavation-based repair methods, encompassing conventional assessment (CA) on fuel combustion of engineering equipment and comprehensive life cycle assessment (LCA) on the materials production, fuel production, traffic delay, and engineering equipment. The results indicate a substantial reduction in carbon dioxide emissions for highway maintenance projects employing high-polymer grouting repair technology. The carbon dioxide emissions were reduced by 76.1% and 87.3% respectively per kilometer. The primary contribution to carbon dioxide reduction is observed during the construction phase and in terms of alleviating traffic delays. An indirect relationship is established between the carbon dioxide emissions of high high-polymer grouting materials and their strength, providing a reference for dynamically selecting material density in maintenance projects. The analysis of potential strategies to reduce CO2 emission in the transport sector and other industrial sectors suggests that the LCA model has the capability to accurately pinpoint the main contributing factors and CO2 emission levels stemming from specific maintenance processes within the intricate transportation system. The emphasis on enhancing the production technology of high-polymer materials is pivotal for further reducing carbon dioxide emissions in the context of high-polymer grouting repair technology.

Enhancing gas production in low-permeability natural gas hydrate reservoirs by the axial water jet slotting and grouting in vertical wellbores

Natural gas hydrate (NGH) is considered as clean energy in the 21st century, and most of the hydrates in the world exist in low permeability reservoirs. However, the exploitation of low permeability hydrate reservoir is not easy to transport gas and water to wellbore, which seriously restricts the production. To enhance production and increase efficiency, an axial water jet slotting and grouting (AWJSG) technology is put forward for the first time, that is, the near-well reservoir is slotted by high-speed water jet along the axis direction, and the slot is filled with foamed mortar material, forming the high-permeability production channel. In this study, the feasibility of AWJSG is analyzed by a numerical production model based on the NGH reservoir in Shenhu area of South China Sea. The results show that with AWJSG operation, the hydrate dissociation efficiency, the cumulative gas production, and the average ratio of gas to water production can be increased by 145.0%, 139.2% and 52.4%, respectively, indicating the efficiency of the proposed method. Furthermore, the yield-increasing effect of AWJSG mainly depends on the number, length, width, height, and permeability of slots. For the stratum and well type in this study, the recommended slotting parameters are a number of 4, a length of 5 m, a width of 0.1 m, a height of 15 m, and a permeability of 500 mD, respectively.

Strata Movement of Overburden-Separation Grouting Working Face and Its Influence on Gas Emission during Mining

Due to its excellent effect of surface subsidence reduction, the overburden-separation grouting (OSG) technology has been widely applied to green mining. However, OSG changes the mine pressure, and the resultant gas emission in the stope remains unclear. Therefore, with the 22301 working face of Tunlan Coal Mine as an example, the overburden deformation and stress distribution in the absence and presence of OSG were studied through numerical simulation and on-site tests. Furthermore, the gas emission law in the stope was contrastingly analyzed. The following results were obtained. With the rise of grouting pressure (GP), the subsidence of strata above the separation layer decreases while that below the separation layer increases; the heave displacement of floor strata below the coal seam gradually decreases. OSG significantly changes the geometric shape and range of the overburden stress relief zone. As the GP rises, the gas enrichment area moves downward continuously and shrinks spatially. Horizontally, the ranges of the stress relief zone and the free space in the goaf shrink, while the range and compaction degree of the compaction area gradually grow. After OSG, the total amount of gas emission in the working face falls by 52.2%.

Technologies for large cross-section subsea tunnel construction using drilling and blasting method

This paper reviews the progress made by our research team in the construction of large cross-section subsea tunnels using the drilling and blasting method. Our research on the prevention and control of water inrush during the construction period and the control of water leakage and discharge during the operational period is introduced. It includes a compound grouting technology for high permeable ground, an elaborate process control method for large cross-section tunnels and an active controlling waterproof-drainage system. These achievements were applied to the first two large cross-section subsea tunnels in China, namely the Xiamen Xiang’an Tunnel and the Qingdao Jiaozhou Bay Tunnel. Thereafter, the technical mode of subsea tunnel construction using the drilling and blasting method was established, providing a theoretical basis and systematic technical support for the safe construction of large cross-section subsea tunnels under complex conditions.

Implementing the Technologies of Additional Impermeable Layers in a Building of the Monuments Office (Káčerov Majer) from a Sustainability Point of View

This article presents the results of an experiment that involved applying additional impermeable layers on an historical building in the area of Káčerov Majer. The building showed a high level of waterlogging, which was detected by an initial inspection and subsequent moisture measurements that involved taking a set of measurements and recording the data in a spreadsheet linked to the plan view of the building. Then, a suitable method was devised to prevent rising damp and to assist in drying out the building. Several measurements after the application of remediation interventions were used for this purpose. The interventions, together with a comprehensive restoration, were intended to contribute to the reuse of the building, and thus its sustainability from technical, environmental, functional, and economic points of view. The aim of this research was to demonstrate the degree of effectiveness of undercutting technology in combination with local application of stainless-steel sheet piling and grouting technology, as one example of sustainability, which is a very relevant topic at the moment. These technologies were intended to provide remediation of the building against rising damp which was destructive to the structure. The environment in this building was affected by moisture and was also unhealthy, which made it difficult to use the building. For these reasons, it was necessary to take radical steps, by applying invasive anti-moisture technologies. The appropriateness and effectiveness of the technologies used have been evidenced by the results published in this article that have also been supplemented by photographs before and after the application of the remediation measures. This research demonstrates the effectiveness of the interventions and the need to also implement them on certain selected buildings where there is a high level of dampness causing degradation. From a sustainability point of view, such a step is essential to preserve the life of such structures and their continued use. The results of this research clearly demonstrate the appropriateness of comprehensive restoration of selected historical buildings, complemented by invasive damp-proofing interventions, as one of the important aspects of the sustainability of deteriorating monuments, whose numbers are constantly increasing.

Cement-Based Grouting Technologies for Radwaste and Toxic Waste Storage

Cement-Based Grouting Technologies for Radwaste and Toxic Waste Storage

Review of Jet Grouting Practice around the World

This paper aims to make a historical review of jet grouting techniques and encountered problems at different sites in several countries. This review is a good guide to understanding the performance and limitations of improved soils or lands. The basic concept of jet grouting technology is to use cement as a binder to accelerate the hardening process of an admixture of material grout and soil. The different case history was conducted in both sand soil and clay soil in the horizontal and vertical direction. Other papers on field construction showed that the grout can be gelled within 5-10 minutes. Due to different cases and studies, these will help improve soil by supporting the foundation load with a minimal settlement. The Jet grouting technology can be used in difficult situations, confined and unconfined areas, or places with light equipment. Although the jet grouting technique is an ideal modification technique compared to reinforcement and ground treatment support or serves the foundation, Dams and excavations will save time and cost and increase the bearing capacity.

Research on Sustainable Mining and Water Prevention in Large Open-Pit Water Deposits

Due to the impacts on the ecological environment, production safety and the economic benefits of large open-pit water deposits, there is no longer a single drainage method within the pit that can be used to meet the need for further deep mining. Therefore, curtain grouting technology is proposed for use in the prevention and control of mine water. The flow control equation of slurry in vertical fissures under the influence of self-weight stress was derived, and a three-dimensional visualized laminated jointed rock grouting model was developed independently to study the slurry transport mechanism, diffusion pattern, and sealing mechanism, which verified the correctness of the control equation. Field trials of industrial curtain grouting were also carried out at the mines, and the effectiveness of curtain water blockage was tested using visual analysis, inspection hole detection, and geophysical exploration methods. The results showed that after grouting the curtain, water-conducting cracks in the formation can be filled well and sealed, and the curtain has a good water-blocking effect. A complete set of diversified value-taking grouting systems is obtained, which can ensure the development of a green, safe and sustainable mine in the future.

Analysis of Grouting Technology in Building Construction

The application of grouting technology in housing construction is to inject liquid grout into the cavities and cracks of housing construction. After it solidifies, the stability of housing construction can be improved. Grouting technology is not only very convenient but is also environmental-friendly, and it is relatively low-cost. Therefore, it is widely used in housing construction. In this paper, the types of grouting technology and its application advantages in housing construction are analyzed, and specific application strategies are put forward, in hopes of improving the quality of housing construction.