scholarly journals Development of Modified Grouting Material and Its Application in Roadway Repair Engineering

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yang Yu ◽  
Zhengyuan Qin ◽  
Xiangyu Wang ◽  
Lianying Zhang ◽  
Dingchao Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Mass Ratio ◽  
Control Effect ◽  
Grouting Pressure ◽  
Grouting Material ◽  
Wide Range ◽  
Grouting Reinforcement ◽  
Grouting Materials

It is very extraordinary for the success of coal mine roadway grouting with the following factors of high early strength, good fluidity, and convenient pumping, but the existing grouting materials make it difficult to achieve the above characteristics at the same time. Therefore, a modified grouting material is developed, which is composed of two kinds of dry materials A and B, which are mixed with water and in equal amounts. The physical and mechanical properties of modified grouting materials under different ratios were tested by laboratory orthogonal test, and the optimal ratio of grouting materials and additives was obtained: (1) the water-cement ratio is 0.8 : 1; (2) base material: the mass ratio of cement, fly ash, bentonite, and water is 1 : 0.3 : 0.1 : 1.44; (3) admixture: the mass ratio of water reducer C, accelerator D, and retarder E is 1.5% : 0.05% : 0.3%. The basic properties of the modified grouting materials were studied from the aspects of slurry flow state, diffusion range, and grouting parameters by using the numerical simulation method, and the reinforcement mechanism of slurry to the broken surrounding rock properties of the roadway was revealed: (1) the grouting pressure is the main factor affecting the slurry diffusion radius; (2) the mechanical properties of the roadway surrounding rock are improved, the plastic zone and deformation of surrounding rock are reduced, and the active support function of the anchor and cable is enhanced through grouting reinforcement; (3) the control effect of the roadway is improved, and the balanced bearing with anchorage structure of the roadway surrounding rock is realized through grouting reinforcement. On this basis, the modified grouting material is applied to roadway repair and reinforcement engineering practice. The field monitoring data show that the production practices were guided by roadway repair and reinforcement technology with the modified grouting material, as the core of the roadway surrounding rock control effect is good, and the modified grouting material has a wide range of application prospects.

scholarly journals A More Realistic Study on the Mechanical Properties of CFRC Composite Grouting Material under a Long-Term Water Immersion Process

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Yao Xiao ◽  
Huafeng Deng ◽  
Jianlin Li ◽  
Eleyas Assefa
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Fiber ◽  
Water Immersion ◽  
Fiber Content ◽  
Grouting Material ◽  
Bonding Properties ◽  
Grouting Materials ◽  
Dam Foundations

The long-term effect of water immersion on the mechanical properties of CFRC composite grouting materials was studied by using five different carbon fiber contents (0, 0.25%, 0.50%, 0.75%, and 1.00%). The direct shear and long-term immersion tests were performed based on the specified and optimum values of carbon fiber content, respectively. The results showed the following: (1) the application of carbon fiber significantly improved the shear resistance of CRFC composite grouting material by using “reinforcing” and “anchoring” actions. The shear strength of the specimen was increasing by 5.66%∼43.41% when the carbon fiber content increased from 0.25% to 1.00%. After a comprehensive analysis, the optimum carbon fiber content was found to be 0.75%. (2) The degradation in the compressive and tensile strength of CRFC composite specimens exhibited a consistent trend (i.e., a steep gradient was gradually followed by a gentle slope) under a long-term water immersion process. About 90% of the total degradation in the compressive and tensile strength has occurred in 90 immersion days (i.e., 16.05% and 18.45%, respectively). In comparison, the degradation in the tensile strength (20.05%) was slightly higher than the compressive strength (18.16%). (3) Under the long-term water immersion process: the properties of the specimens were gradually deteriorating, the carbon fibers were gradually reaching a fatigue stage, and the bonding properties of carbon fiber was decreasing, which resulted in a reduction in the compressive and tensile strength. The uniaxial compression failure mode changed from brittle to ductile, and the development of local failure was very noticeable. Based on the findings of this paper, groundwater has a significant impact on the mechanical properties of grouted rock mass such as dam foundations and abutments. Therefore, the degradation in the grouting materials has to be considered in practical cases.

scholarly journals An Experimental Study on the Reinforcement of Silt with Permeable Polyurethane by Penetration Grouting

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Chaojie Wang ◽  
Qi Liu ◽  
Chengchao Guo ◽  
Yangyang Xia ◽  
Yanjie Hao ◽  
...  
Keyword(s):  
Soil Structure ◽  
Coupling Effect ◽  
Interaction Mechanism ◽  
Engineering Practice ◽  
Grouting Pressure ◽  
Grouting Material ◽  
Jet Grouting ◽  
Diffusion Pattern ◽  
Diffusion Speed ◽  
Penetration Grouting

To meet the demand of antiseepage and reinforcement of soil dams, a kind of permeable polyurethane grouting material was developed. A visual steady-pressure grouting test device was designed to study the law of polyurethane diffusion and reinforcement in silt under different pressure, and the interaction mechanism of grout and soil body structure was explored microscopically. The results showed that, with the increase in the grouting pressure, the diffusion speed rose, and the diffusion pattern of grout in the soil also changed from permeation diffusion to permeation splitting. Under the effect of grouting pressure, more tiny cracks will occur in the soil structure, leading to the use of more grout, thus increasing the strength of the consolidated soil by more than 10 times. The results of SEM-EDS and mercury intrusion test proved that the polyurethane had a significant filling effect on the soil structure, which could effectively reduce the porosity of the soil and cement the soil particles through wrapping, complexing, and hydrogen bonding, thereby improving the soil properties. Moreover, the results revealed from a microscopic perspective that the grouting altered the pore structure of the soil structure through the seepage-erosion-splitting coupling effect, but when the grouting pressure exceeded 0.4 MPa, the soil particle and grout would be partially remixed and arranged closely, showing a phenomenon of jet grouting. Finally, the material was used in engineering practice, achieving a satisfactory grouting treatment effect.

scholarly journals Roof Failure Mechanism and Control Technology of Large Section Open-Off Cut in Soft Rock Strata with Thin Thickness

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Chen Li ◽  
Jun Li ◽  
Xiaoyong Lian ◽  
Yongen Li ◽  
Qi Xue ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Failure Mechanism ◽  
Underground Mining ◽  
Soft Rock ◽  
Mechanical Analysis ◽  
Field Monitoring ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Control Effect ◽  
Rock Strata

The open-off cut is used for equipment installation of working face before underground mining, and its sectional size is larger than that of the mining roadway. Therefore, the stability of open-off cut surrounding rock determines whether the panel can be put into operation. To solve the roof instability of open-off cut in the Wanli No.1 coal mine, the roof failure mechanism of open-off cut under weak composite rock strata with thin thickness was studied by field monitoring, theoretical analysis, and numerical simulation. First, the characteristics of surrounding rock and the basic law of strata behaviors were obtained by detailed field monitoring. Afterward, FLAC3D numerical simulation and mechanical analysis were used to obtain the main mechanical control parameters of surrounding rock instability, and the existence of a soft interlayer above the roof is the main cause of roof instability. Based on this, the supporting parameters of the open-off cut were optimized and adjusted. The optimized parameters were applied to the adjacent 31207 open-off cut. The engineering practice showed that the optimized supporting parameters have an ideal control effect on roof stability.

scholarly journals Research on the Reuse of Discharged Soil from EBP Shield Tunnels in Synchronous Grouting Material

2022 ◽  
Vol 2022 ◽  
pp. 1-15
Author(s):  
Guijun Luo ◽  
Chao Xiao ◽  
Yuan Liu ◽  
Kejun Feng ◽  
Qingguo Ren
Keyword(s):  
Engineering Application ◽  
Fine Sand ◽  
Surface Settlement ◽  
Practical Significance ◽  
Filling Rate ◽  
Performance Requirements ◽  
Grouting Pressure ◽  
Grouting Material ◽  
Grouting Materials ◽  
Epb Shield

Great practical significance and engineering application value can be achieved when the large amount of discharged soil produced by EPB shield tunnels is recycled and comprehensively utilized. As one of the key processes of shield construction, synchronous grouting needs a large amount of bentonite, cement, fly ash, sand, and other materials. The research on the reuse of shield muck as synchronous grouting material is carried out based on Zhengzhou subway project. The physical properties and phase of the discharged soil from EPB shield tunnels are studied by using laboratory tests and XRD. The statistics show that the shield muck meets the performance requirements of bentonite and fine sand in synchronous grouting materials. The optimal grout ratio of the reused muck is obtained based on the optimization idea of multiobjective programming by MATLAB. Considering the combined effect of seepage field, stress field, and the timeliness of the grout, the influences of grouting pressure and the filling rate of synchronous grouting on surface settlement, plastic zone of strata, and segment deformation are analyzed by using finite difference method. The results prove that the surface settlement and segment deformation can be better controlled when the grouting pressure is at 0.18 MPa and the grouting rate is at 120%–150%.

Application of Grouting Technology

2010 ◽  
Vol 163-167 ◽  
pp. 471-474
Author(s):  
Wen Yi ◽  
Yong He Wang ◽  
Rui Zhou
Keyword(s):  
Engineering Practice ◽  
Construction Technology ◽  
Wide Range ◽  
Key Issues ◽  
Grouting Reinforcement ◽  
Inspection Techniques ◽  
Construction Works

The wide range of grouting technology, theory and construction technology are relatively mature, but as a result of the promotion of its application is still uneven, and grouting construction works are hidden, so often cost more is spent in grouting reinforcement work, but the expected results of the problem is not yet achieved. In this paper, it is given a comprehensive summary of the effect of grouting and the application of inspection techniques. It is given analysis of the key issues of technology, and hopes to provide reference with the grouting reinforcement of engineering practice.

Research on Grouting Materials for Underground Construction Projects

2021 ◽  
Vol 1036 ◽  
pp. 319-326
Author(s):  
Hao Ran Duan ◽  
Peng Zhao ◽  
Lei Qin ◽  
Feng Jiao Shi
Keyword(s):  
Environmental Pollution ◽  
Large Scale ◽  
Raw Materials ◽  
Development Trend ◽  
Engineering Practice ◽  
Underground Engineering ◽  
Chemical Grouting ◽  
Cement Grouting ◽  
Grouting Material ◽  
Grouting Materials

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.

The Regression Prediction Analysis of Grouting Concretion Stone’s Strength Based on SVR

2013 ◽  
Vol 859 ◽  
pp. 171-176 ◽  
Author(s):  
Jin Sheng Lei ◽  
Jian Fei Chen ◽  
Xue Ting Cao ◽  
Qian Feng Wang
Keyword(s):  
Support Vector Machines ◽  
Support Vector ◽  
Grouting Pressure ◽  
Grouting Material ◽  
Strength Based ◽  
Vector Machines ◽  
Gravel Soil ◽  
Strength Tests ◽  
Grouting Materials ◽  
The Relationship

Cement-based grouting material is used for the grouting of gravel soil, and do compressive strength tests for the grouting concretion stones. Use the method of support vector machines for regression (SVR) to deal with the test data and predict the grouting concretion stones strength. Specific methods are as follows: randomly select 20 groups of the specimens for training, the remaining specimens for predicting, and then establish the relationship between the performance of soil body medium, grouting materials, grouting pressure and strength of concretion stones strength. The research results show that the support vector machines method can judge the sensitivity to impact indicators of grouting stones strength, and predict and analysis the grouting stones strength under multiple factors.

scholarly journals Instability Analysis and Reinforcement Support Technology of Coal-Rock Interbed Roadway in Gaojiazhuang Coal Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Chaolin Liu ◽  
Guohua Zhang
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Coal Mine ◽  
Surrounding Rock ◽  
Rock Deformation ◽  
Distribution Characteristics ◽  
Control Effect ◽  
Ultrasonic Detection ◽  
Wide Range ◽  
Surrounding Rock Deformation

In order to effectively solve a series of problems such as the difficulty of coal and rock interbed roadway support in Gaojiazhuang Coal Mine and get a scientific and reasonable optimization scheme of surrounding rock support, theoretical analysis, numerical simulation, ultrasonic detection, field-effect test, and other means are adopted to analyze the instability of coal and rock interbed roadway. The results show that the interbedded roadway has weak interbedded cementation, and its ore pressure is more intense due to the influence of its interbedded weak structural plane. Based on Mohr’s strength envelope principle, it is proposed that horizontal stress is the main factor that causes a wide range of shear displacement, penetration crack, and surrounding rock failure of the roof of this kind of roadway. Through the finite element numerical simulation analysis, the deformation and failure law, stress distribution characteristics, and failure area distribution characteristics of coal and rock interbedding roadway surrounding rock are theoretically revealed, and the control effect of different support schemes on roadway surrounding rock deformation is greatly different. Based on the ultrasonic detection technology, it is proved that the roadway side failure has strong zoning characteristics, and the failure range and stress distribution range of the surrounding rock of the belt roadway in the 2103 working face of Gaojiazhuang Coal Mine are detected. Finally, the coupling strengthening support scheme combining prestressed anchor cable and bolt is proposed. The engineering application and the observation of surrounding rock deformation show that the reinforced support technology can effectively enhance the stability of the surrounding rock of the interbed roadway in Gaojiazhuang Coal Mine, and it has a good reference for the surrounding rock conditions of this kind of roadway.

scholarly journals Study on Sensitivity Parameters Analysis of Grouting Reinforcement Underpassing Existing Subway Tunnel by Numerical Modeling

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zaiqiang Hu ◽  
Bin Ma ◽  
Xingzhou Chen ◽  
Lili Chen
Keyword(s):  
Pore Pressure ◽  
Principal Stress ◽  
Surrounding Rock ◽  
Surface Settlement ◽  
Stress Difference ◽  
Reinforcement Effect ◽  
Subway Tunnel ◽  
Grouting Pressure ◽  
Grouting Reinforcement ◽  
The Stability

When carrying out construction that underpasses existing subway tunnels, the surrounding rock is frequently disturbed. Therefore, it can loosen easily and become unstable, which makes its stability difficult to control. Here, we considered an existing subway tunnel in a certain subway section and used orthogonal experiments to design a simulation program as well as the UDEC (Universal Distinct Element Code) simulation software to determine the influences of four factors (i.e., grout density, grouting pressure, dynamic shear force, and viscosity) on the grouting reinforcement effect. The following results were obtained: (1) the combination of the construction method and the grouting parameters strongly influences the reinforcement effect on the surrounding rock of the tunnel. The grouting pressure is not directly proportional to the stability of the surrounding rock. The dynamic adjustment of the relationship between the grouting pressure and the grout density can effectively improve the stress state of the surrounding rock of the tunnel, control surface settlement and deformation, and reduce the section reduction rate of the tunnel. (2) The distribution of joints is closely related to the failure area and form of the surrounding rock of the tunnel. For surrounding rock with well-developed joint fissures, an excessively high grouting pressure should not be used as they are unstable. (3) The effective bearing range of grouting-reinforced surrounding rock is dependent on the pore pressure and principal stress difference. The area where the pore pressure is 70–80% of the initial grouting pressure is the effective bearing range of the grouting-reinforced surrounding rock. The stability of the surrounding rock increases with decreasing principal stress difference and increasing range. (4) The actual monitored data show that the surface settlement can be effectively reduced by handling of grouting reinforcement parameters flexibly, which can meet the control standards.

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