Jet Grouting Technology Research Articles

Experimental and theoretical analysis of single-jet column and concrete column using double-jet grouting technique applied at Al-Rashdia site

Abstract Progress in jet grouting technology has been focused on the cutting-edge observer of jets, which aims to generate large columns of jet grouting and increase the activity of construction sites. Since jet grouting techniques vary from conventional grouting methods to modern techniques, they can be used in a variety of soil types and their application areas are expanding quickly. So, grouting methods have become very popular methods for subsoil strengthening. This article includes finding the physical and mechanical properties of the soil of the AL-Rashdia site, using a single-jet grouting machine and a steel model to test concrete piles and jet piles, and a double-jet grouting machine to compare the results obtained from laboratory model of one-dimensional jet grouting column pile with those of a one-dimensional concrete pile. The comparison showed that the settlement of the jet pile was smaller than that of the concrete pile and the bearing load was higher with jet columns giving a high bearing capacity comparable with the concrete pile. Shen’s method is more adequate to find the ultimate bearing load and the settlement for this load. Also, the ultimate pile ratio was 115.63% for the jet column, and the ultimate pile ratio for the concrete column was 123.49%. The compressive strength of the core sample of jet columns was large which improved the bearing capacity of the foundation.

Experimental study on the stabilization and anti-seepage treatment of lead and zinc elements in heavy metal tailings pond using cement slurry containing heavy metal stabilizing agent

The release of heavy metal elements in heavy metal tailings ponds not only causes environmental pollution but also poses potential hazards to human health. Therefore, it is of great significance to stabilize heavy metals and apply anti-seepage treatment to tailings ponds. In this paper, the tailings in the Shenxiandong lead-zinc tailings pond in Yunnan Province, Southwest China, were analyzed. The adsorption effects of different natural stabilizing agents on lead (Pb) and zinc (Zn) in tailings were investigated. Orthogonal and modification experiments were used to identify the most effective stabilizing agent. This agent was then combined with a high-pressure rotary jet cement slurry to investigate the properties of the resulting consolidation body and its effect on heavy metal solidification. The results show that the tailings are more likely to release heavy metal elements into the environment. The results of the orthogonal experiments show that the stabilizing agent CCA, which is a combination of fly ash, attapulgite, and Na-bentonite in a 2:1:2 ratio, effectively adsorbs Pb and Zn elements in the tailings. The stabilizing agent CCAPT is created by modifying CCA with 7% H3PO4 at pH of 12 and heat treating at 200 °C. CCAPT demonstrates a 97.2% improvement in stabilization efficiency for Pb and a 94.1% improvement for Zn compared to CCA. The combination of CCAPT and cement slurry resulted in a 25.6% increase in compressive strength and a 29.5% decrease in permeability coefficient compared to the cement slurry formed consolidation body. The core-flooding experiment shows that the residual leachate after consolidation of “5% CCAPT + cementitious slurry” contains only 35.6 μg/L of Pb and 29.2 μg/L of Zn. These concentrations are significantly lower than the national emission requirements. This study presents an experimental foundation for further investigation into the use of high-pressure jet grouting technology to seal tailings ponds.

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.

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.

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.

Влияние теплопроводности материалов контактных поверхностей на тепловой баланс элементов гидросъемника для струйной цементации грунтов

The paper is deals with the influence of thermal conductivity and the materials of the contact surfaces of the drill shaft and the sealing element on the change in the thermal balance of the structural unit «drilling string» used in the jet grouting technology to fix weak and unstable types of soils. A model with nodes for the computational grid of the “hydraulic puller” assembly unit is shown, part of which are the considered drill shaft and sealing elements. The temperature values are calculated by the finite element method in the «Siemens Femap’s» environment depending on the change in the thermal conductivity coefficients of the contacting elements. Calculations were carried out for the fourth part of the indicated model, due to the axisymmetry of the problem being solved, this made it possible to significantly reduce the amount and time of calculations. Graphs of the corresponding dependence are constructed for a number of points located in the characteristic areas of the hydraulic stripper. Also, by power regression, expressions were obtained that allow calculating the temperature values in the indicated areas of the considered assembly. The obtained dependencies will make it possible in the future to select the material for the drill shaft of the hydraulic puller based on the optimal ratio of the thermal conductivity of the shaft, its corrosion resistance, determined by the chemical composition of the steel and the thermal conductivity of the sealing.

Enhanced heat extraction performance from deep buried U-shaped well using the high-pressure jet grouting technology

Heat extraction from the single-well geothermal heating system (SWGHS) is significantly restricted by the high thermal resistance of the surrounding host rocks. To improve heat production efficiency of this geothermal system, the high-pressure jet grouting (HPJG) technology is proposed to enhance thermal output in deep buried U-shaped well (DBUSW) system. By means of this technology, an artificial jet grouting column (JGC) with high thermal conductivity is built near the horizontal well segment. The emphasize of this work is to evaluate the feasibility and efficiency of the proposed heat production method. Numerical simulations were conducted via a field validated model from in-situ experiments in Xian. Results demonstrated that average annual heat production rate is improved by about 22% in the 30-year heating period, with building an artificial JGC with 1.0 m radius near the wellbore. These results indicate that the proposed method is a promising strategy for enhancing thermal output in the DBUSW. Sensitivity analyses suggest heat production rate and outlet temperature are mainly controlled by the radius of the JGC, while very high JGC thermal conductivity has less effect. Given the field conditions, the suggested thermal conductivity and radius of artificial JGC is 30 W/m °C and 2.0 m, respectively.

Study on Gas Hydrate Reservoir Reconstruction for Enhanced Gas Production in the Shenhu Area of the South China Sea Based on a 3D Heterogeneous Geological Model

Natural gas hydrate (NGH) has the huge exploitation potential for clean energy in the current world energy pattern. Its total organic carbon storage is about twice the sum of carbon content of oil, gas, and coal and hence attracts the attention of the world. China has carried out some gas hydrate exploitation works and delineation of three gas hydrate deposits whose reserve scale is over 100 billion cubic meters, and the NGH resource is abundant. The NGH reservoir in the South China Sea is of low porosity and permeability, is unconsolidated, has poor cementation, and is easy to fragment in hydrate production. On the one hand, the condition of low porosity and permeability around the well would severely reduce the production effect; on the other hand, the hydrate decomposition would more easily bring wellbore instability caused by stratum stress change. Therefore, to achieve safe and efficient exploitation of NGH, proper reservoir reconstruct technology needs to be chosen for enhancing the reservoir’s permeability and stability. This paper chose the Shenhu area of South China Sea as the research area, constructed the three-dimensional heterogeneous geological model of hydrate-bearing sediments which can be approximated realistically to depict, then used high-pressure jet grouting (HPJG) technology to reconstruct the hydrate reservoir, optimized the grouting hole direction, location, and spacing, and assessed the productivity increasing effect. The research results show the following: (a) Because of the higher hydrate saturation (SH) and lower permeability (k) around the well, the HPJG in the vertical direction was profitable for reservoir productivity. (b) Considering the heterogeneous SH and k in the horizontal direction, the HPJG in the front of the horizontal well was profitable for the reservoir productivity. (c) The HPJG spacing needs to be properly designed in combination with the absolute standard (VP), the relative standard (RGM), and the specific production index (J). (d) Under the conditions of this paper setting, the optimal HPJG reconstruction scheme is as follows: the HPJG in the vertical direction was arranged at the front of the horizontal well, and the spacing between the holes was 10 m. The productivity after reconstruction ranged up to 55.69% compared with before.

Jet-Grouting Technology for Reinforcement Strata Disturbance After Sand Mining

During the construction of a bridge, due to the deep sand mining in the riverbed at the bridge site, a sand mining disturbance stratum is formed at the bridge site, and it has an impact on the construction quality of the pile group foundation. In this paper, in view of the special geological conditions caused by sand mining, the high-pressure jet grouting method was used to reinforce the disturbed stratum at the bridge site, and a scheme and key construction technology high-pressure rotary jet pile grouting to reinforce the disturbed stratum caused by sand mining is proposed. A three-dimensional finite element model of the pile group before and after reinforcement of the disturbed stratum by high-pressure jet grouting method is established. The distribution characteristics of the lateral displacement of the borehole wall in the disturbed stratum before and after reinforcement are compared and analysed. Application on an actual bridge proves that the high-pressure jet grouting method has a good reinforcement effect on the disturbed stratum, which effectively solves the phenomenon of hole expansion and pile casing falling in the construction process of the pile foundation caused by sand mining disturbance and improves the working performance and construction quality of the pile group foundation. The high-pressure jet grouting technique for reinforcement of disturbed stratum is proved to be effective in practice.

FILTRATION PROBLEM WITH NONLINEAR FILTRATION AND CONCENTRATION FUNCTIONS

ncient architectural buildings are of great value for all modern humanity. Over time, under the influence of vibrations, water and other man-made and natural factors, the foundations of such buildings are destroyed, the soil structure changes. Currently, one of the most popular methods of strengthening soils and strengthening foundations is the jet grouting technology. When the liquid grout passes through the porous rock, the suspended particles of the grout form a deposit. In this paper, we study a one-dimensional model of suspension deep bed filtration in a porous medium with different particle capture mechanisms. The considered filtration model consists of the balance equation for the masses of suspended and retained particles and the kinetic equation for deposit growth. In this case, the deposit growth rate is determined by the concentration function of suspended particles, which, in turn, depends on the properties of the suspension and the geometry of the porous medium. The solution to the problem is obtained for linear and non-linear concentration functions. An asymptotic solution of the problem is constructed for both types of functions near the concentration front of suspended and retained particles. It is shown that the asymptotic and numerical solutions are close over a long time interval.

Application of Fluidized Bed Furnance Bottom Ash in Civil Engineering – A Review

For several years there has been widespread and open discussion about climate problems and human responsibility for the generated waste. The number of regulations has led to a search for applications for by-products of combustion. Moreover, the forecasted economic crisis additionally motivates to use every possible material to reduce the cost of manufacturing activities. Efficient waste management is a key element for Polish companies in their efforts to reduce their negative impact on the environment. Fluid combustion of fuels in the Polish power and heat industry still belongs to relatively new technologies. Despite the application of the most technologically advanced processing methods, bottom ashes from fluidized bed boilers are still reluctantly used. The author sees possibilities of using bottom ashes in geotechnical works. The aim of this review is to present the existing source papers relating to the use of bottom ashes in construction processes. A particular area of interest is the use of said ashes in jet-grouting (JG). The paper briefly refers to fluidized bed combustion technology as a source of combustion byproducts. The author pay special attention to the characteristics defining the characteristics of the ashes. The reader's attention will then be drawn to jet-grouting technology. References can be found to the methodology of general cement-soil testing. Due to the nature of the use of JG, the focus is particularly on their strength, water-permeability and frost resistance properties. Due to the need to determine the internal structure of the cement-ground, attention was also paid to the possibility of using X-ray computed tomography for soil cement testing.

Enhanced gas production from clayey-silt hydrate reservoirs based on near-well reservoir reconstruction using the high-pressure jet grouting technology

Over 90% of the global hydrate resource is accumulated in the fine-grained sediments with very low permeability. Gas production from the low-permeability hydrate reservoirs is significantly restricted by the effective transport of fluids into the production well. To improve gas production from the low-permeability hydrate reservoirs, the high-pressure jet grouting (HPJG) technology is first proposed that involves construction of an artificial jet grouting column (JGC) with relatively high-permeability around the production well using the cellular concrete. In this work, the main target is to investigate the feasibility of this proposed method for enhancing gas production by numerical simulation, aiming at the clayey-silt hydrate reservoirs in the Shenhu area of South China Sea. It is demonstrated that the hydrate dissociation efficiency and the gas productivity greatly improved by about 157% and 110%, respectively, by constructing an artificial JGC with radius of 0.5 m around the production well. The results suggest the proposed method is a promising strategy for enhancing gas production from the low-permeability hydrate reservoirs. This is mainly because the artificial JGC significantly promotes the advance of depressurization and the transport of gas and water within the reservoir. In addition, gas production performance of the proposed strategy mainly depends on JGC radius and JGC height, while the JGC porosity has less effect. For the specified clayey-silt hydrate reservoirs in the Shenhu area, the artificial JGC radius, height, and permeability are recommended as 0.5 m, 30 m, and 1.0 × 10 −12 m2, respectively.

Experimental and Numerical Investigations on Hydraulic Barrier Bottom Plug for Deep Excavations A Case Study

In Vietnam, the solution of designing and constructing deep foundation pits with the geology of sandy or clayey sand is very difficult, especially in case soil mix mud. In some deep foundation pits, the unreasonable treatment solution causes the bottom plug of the foundation pit to be pushed up to the foundation pit or not to pump a foundation pit dried. Solving those problems, this article introduces a particular case study, sealing the bottom of the foundation pit for no14 of Yen Xa drainage works with the Jet grouted bottom plug hydraulic barriers. To treat the soft soil layer, mix organic without breaking the upper soil layers, this solution uses Jet-grouting technology with a mixture of materials including cement, fly ash, blast furnace slag, lime in a reasonable proportion to ensure waterproof and not uplift the massive bottom plug hydraulic barriers when excavating soil in the pit. Results of calculation and acceptance after the foundation pit is completed show that this is a good solution, high reliability and can be applied to seal the bottom of the foundation pit in similar geological conditions.

Modeling of the effect of a high-pressure jet of cement mortar on the surrounding soil environment when performing jet grouting columns using jet technology

The main idea of jet grouting technology is the implementation of processes aimed at changing the characteristics of soils, creating materials with the necessary properties on their basis and forming underground elements with specified parameters from these materials. The high pressure of the cement mortar jet leads to soil blending and its continuous destruction within the radius of impact of the jet. According to some authors, the jet outside the destructive radius does not affect the surrounding soil environment. In compliance with practical studies performed at construction sites in Kyiv, Ukraine, the data on changes in the physical and mechanical characteristics of the soil surrounding the soil-cement column were obtained. This fact led to a more detailed study of the effect of a high-pressure jet on the surrounding soil during the execution of columns using jet technology.

Discussion on Anti-seepage Wall and Anti-seepage Technology of Water Conservancy Project

The water infiltration problem of water conservancy projects is one of the more common problems in the construction of water conservancy projects, which seriously affects the overall construction quality and safety of water conservancy projects. This article studies the causes of water infiltration in water conservancy projects and introduces related anti-seepage technologies, hoping to be a reference for the implementation of anti-seepage projects. Through research, it is found that the factors that cause water infiltration in water conservancy projects include water conservancy project structural changes, environmental factors and construction factors. Relevant personnel can use concrete anti-seepage wall construction technology and high-pressure jet grouting technology to do the relevant anti-seepage work of water conservancy projects.

Determination of the Attenuation Factor via Seismoacoustic Studies in Wells to Estimate the Distribution of Heterogeneities in Artificial Soils

Quality control by hidden works in artificial soils is a relevant problem in construction engineering. Seismoacoustic methods are widely used for its solution. In this work, seismoacoustic well logs in artificial soils manufactured by the jet grouting technology were processes to obtain additional data on the distribution of heterogeneities in an artificial soil. The spectral ratio and frequency shift methods were used to estimate the attenuation factor.

<i>Q</i>-factor determitation with seismoacoustis well logs for estimation of distribution of inhomogeneities in artificial grounds

Quality control in geotechnical engineering is becoming an important issue, especially when products are buried underground. Seismoacoustic methods are widely used for investigations in such structures. In this article seismoacoustic well logs from hidden structures (made by jet grouting technology) are being processed with the goal of obtaining additional information about distribution of heterogeneities in improves grounds. Two methods of estimation Q-factor are used: frequency shift method and amplitude ratios method.

ДОСВІД ВИКОНАННЯ ҐРУНТОЦЕМЕНТНИХ ЕЛЕМЕНТІВ ПО ТЕХНОЛОГІЇ СТРУМЕНЕВОЇ ЦЕМЕНТАЦІЇ В ШЛАК ДОМЕННОГО ВИРОБНИЦТВА

The article describes the first experience in Ukraine in the implementation of ground-cement columns in the blast furnace slags. In accordance with the project to reinforce the soil base during the reconstruction of the place with a canopy in the station for the production of air separation products with the installation of VRU-1400 in the city of Enakievo, experimental work was performed on the territory of the plant to confirm the correctness of the selected technological parameters of Jet Grouting in the actual engineering-geological conditions of the construction site and control of the geometric and strength parameters of cement columns. Two test ground-cement columns were completed, visual and instrumental examination of the jet columns was performed (confirmation of the cylindrical shape, continuity of the shaft of the excavated part of the jet column, measurement of the actual diameter), the cores were drilled from the body of the jet column in the horizontal direction and the material was tested for compressive strength, as well as core sampling in the vertical direction for the entire length of the jet column, testing of soil-cement material. Based on the results of the visual examination, the cylindrical shape of the jet grouting elements was confirmed and the actual diameters were measured, which amounted to 610 ... 640 mm that is more than the required for the project - 600 mm. The selected vertical core confirms the design length of the jet column, the continuity of the body of the jet column and the absence of gaps in the treatment processing with a high-pressure jet of cement solution. According to the results of laboratory tests of cement-slag cylinders selected from horizontal cores, the strength of the material ranged from 4.76 to 7.68 MPa for 24 days of age and 7.96 MPa for 28 days. According to the results of testing cylinders made of vertical core, the minimum strength of cement-slag material was 7.3 MPa, the maximum - 11.2 MPa. The obtained results of the compressive strength of soil-cement material exceed the design strength equal to 2.5 MPa. As a result of the test work on the construction site of the VRU-1400, the correctness of the technical solution for the selection of Jet Grouting technology for reinforcement the foundation base in difficult engineering and geological conditions, namely blast furnace slags, was confirmed.

Application of Jet Grouting technology for the renovation of historic buildings

Renovation and restoration of historic buildings to appropriate functioning is a big challenge for the designer. In the case of this type of buildings, providing them with a new function usually requires the creation of new technical areas for installations and parking spaces. However, the change of function cannot be associated with a fundamental change in the image of the modernised building. In such case, additional areas are obtained by building in the underground spaces under courtyards, streets and often also under existing structures. In certain situations, the mere change in the function of existing underground levels forces an increase in their usable height by deepening of the foundation. Subsequent problem encountered during modernisation is the change in load of individual foundation elements, which is related to the rebuilt static system of the historic structure. In such case, the fragments of foundations require reinforcement that can be implemented by their deepening. One of the methods that enables improvement of the usable properties of basements by increasing their height, as well as reinforcement of the foundations of historic buildings, is jet grouting. This technology resolves many problems associated with limitations in the scope of size of used equipment and access to the place of formation of soil cement elements. Its application allows to significantly facilitate and accelerate the works at the construction site. This study presents the selected examples of the implementation of specialised geotechnical works in the scope of modernisation of historic buildings in Poland, as well as dependence of the strength of soil cement composite on the soil type.

Strength of sandy and clayey soils cemented with single and double fluid jet grouting

Innovations in jet grouting technology have primarily focused on the cutting efficiency of the jets, with the aim of creating larger columns and increasing the productivity of construction sites. Relatively little attention has been paid to the consequences of the grouting system on the mechanical properties of the formed material. This paper investigates this aspect by analysing the results of two field trials carried out in both sandy and clayey soils, where single and double fluid jet grouting were simultaneously performed, with varied grout composition and injection parameters. Parallel uniaxial compressive tests on samples cored from the columns show that the material formed with the double system is systematically lower in strength than the material formed using the single fluid system. The mineralogical composition of samples cored from the columns was analysed by performing parallel Scanning Electron Microscopy (SEM), X-ray diffraction analysis (XRD), Differential Thermal Analysis (DTA) and Thermo-Gravimetric Analyses (TGA) to determine the reasons for this difference. A lower proportion of cementitious products, an accelerated carbonation of portlandite and a less homogeneous distribution of cement hydration products was found on the surface of the soil particles of the double samples than for the single fluid columns.