Reinforcement Project Research Articles

Requisition–Compensation Balance Relief for Hydraulic Projects Based on Cultivated Land Quality Improvement

Requisition–compensation balance is a type of cultivated land protection system in China. The implementation of hydraulic projects has changed the natural conditions unfavorable to the development of agricultural production and effectively improved the quality of cultivated land. This means that the requisition–compensation balance of cultivated land policies for hydraulic projects should be treated differently. Starting from the example of the requisition–compensation balance of hydraulic projects, this paper analyzes the four major factors of cultivated land quality, namely nature, space, ecology, and economy, from the perspective of cultivated land quality. The productivity of cultivated land is selected as the main index. Based on the principle of ensuring the balance of total grain output value, a corresponding quantitative system is constructed. The measurement of cultivated land quality change and that change’s impact on the requisition–compensation balance of cultivated land are explored. In this paper, the constructed quantitative system is tested by taking the local reinforcement projects of Pizhou Luoma Lake and Zhongyun River as examples. Through an analysis and calculation of the selected cases, the quality of cultivated land in Pizhou City was found to have increased by 92.87%, in keeping with the balance of total grain output value. A relief strategy involving the requisition–compensation balance of cultivated land for hydraulic projects is put forward. This strategy provides the theoretical basis for the revision of the policy of requisition–compensation balance of cultivated land for hydraulic projects.

Criterion of Grouting Pressure in Regional Advance Grouting Treatment to Prevent Water Disaster from Karst Aquifers in Coal Seam Floors.

The deep mining of coal mines in North China faces the serious threat of water inrush from karst aquifers in the coal seam floors, and regional advance grouting technology (RAGT) is an effective means to prevent and control such disasters. However, it is difficult to choose the grouting pressure during the implementation of RAGT, and excessive grouting pressure will lead to the splitting of karst fracture and reduce the grouting effect. In this study, based on the Bernoulli equation, the relationship between the ground grouting pressure and critical grouting pressure during grouting is established. Based on the Hoek–Brown (H-B) strength criterion and a fracture mechanics analysis of hydraulic fracturing, a theoretical equation of the critical grouting pressure for fracture splitting during grouting is obtained. The determination methods of the main parameters, such as the length of the fracture, internal friction angle, and H-B constant of the intact rock and geological strength index, and their effects on the critical grouting pressure, are discussed. The results show that the joint influence of the H-B constant and geological strength index of the intact rock is the key factor influencing the critical grouting pressure. The theoretical research results are applied to the Xujiazhuang limestone grouting reinforcement project of the floor of coal seam 11 in the Zhaoguan coal mine. The critical grouting pressure of the aquifer is determined to be 14.54 MPa, which guides the smooth implementation of the project.

Study on Creep Mechanical Properties of Non-Water Reacting Polyurethane Grouting Material

Non-water reacting polyurethane is a new type of grouting material for support reinforcement and emergency rescue, whose creep mechanical behavior is directly related to the stability and safety of the reinforcement project. To investigate the creep properties of non-water reacting polyurethane grouting material, a series of multistage loading creep tests were performed under uniaxial compression conditions. Then, the creep curves, creep strain rate, and creep failure modes of non-water reacting polyurethane grouting material were obtained. In addition, the effects of temperature and density on the creep properties of non-water reacting polyurethane grouting material were also analyzed. Finally, based on the finite difference program, the numerical simulation of the uniaxial compression creep test of non-water reacting polyurethane grouting material was conducted by employing the Burgers–Mohr creep model. The simulated creep curve was in good agreement with the test curve, which verified the feasibility of the model to describe the creep characteristics of non-water reacting polyurethane grouting material. The research results can provide a reference for studying the creep behavior of polyurethane grouting material and also contribute to the development and application of polyurethane material grouting technology.

Triaxial Creep Behavior of Silted Soil in front of Dam Based on Fraction Derivatives Theory

Increasing dam height on reservoir alluvium in front of dam is a kind of reinforcement construction method, which is widely used in the reinforcement projects of dangerous reservoirs in mountainous areas of southern Ningxia. The creep deformation of silted soil in front of dam significantly influences dam stability. To understand the creep properties of silted soil, the triaxial drained shear creep tests of silted soil sampled are conducted under different confining pressures (100 kPa, 200 kPa, and 300 kPa). Meanwhile, a new fractional-order creep constitutive model for silted soil is put forward by combining the improved fractional Maxwell model with the fractional Bingham model in series. The parameters are determined using the nonlinear least-squares method, and the proposed model is also used to fit the triaxial shear creep test results. All comparisons between predicted and measured values show that the developed creep model can characterize the mechanical characteristics of the whole creep process of silted soil well.

Numerical Simulation of the Hydraulic Performance of Spillway of Goushuipo Reservoir

Spillway is an important flood control facility for hydraulic architectures, whether the design and layout of the spillway are reasonable or not can directly affect the safety of hydraulic architectures and the investment of the entire project. To discuss the rationality of the designed reinforcement scheme for spillway of Goushuipo Reservoir in China, this paper employed the Computational Fluid Dynamics (CFD) methods, Volume of Fluid (VOF) model and Re-Normalization Group (RNG) model to simulate the water surface line of spillway under different verified flood standard conditions based on the measured data of water surface line of spillway of the Goushuipo Reservoir. By comparing with the test values, it’s verified that the simulation results are of high accuracy; then on this basis, this paper analyzed the relationship between water level and water flow of spillway under different conditions and other hydraulic performance such as the water flow state. Moreover, according to the simulation results, this paper analyzed the problems with the original design scheme and further proposed an optimized scheme: the two-step water-drop energy dissipation scheme for the Goushuipo Reservoir, and performed numerical simulation on the optimized scheme. At last, the simulation results proved the rationality of the optimized scheme, and the research findings of this paper provide useful references for the reinforcement project of the target reservoir in the future.

Analisis Kinerja Alat Berat Pada Proyek Normalisasi dan Perkuatan Tebing Sungai

The purpose of this study was to analyze the performance of heavy equipment and the duration of time required to complete the Windo River Cliff Normalization and Reinforcement Project, Pamandati Village, Laeya District, South Konawe Regency. The results showed that the excavator's performance in excavation work (mechanical) was 38.68 m3/hour, dump truck 2.99 m3/hour. As for the embankment work imported from outside, the performance of the excavator is 98.53 m3/hour and the dump truck is 3.05 m3/hour. Where the duration of time required to complete the excavation work (mechanical) with an excavator is 12 days and for embankment work imported from outside is 2 days..

Discussion on the Quality Management Model of Small Dangerous Reservoir Reinforcement Project

Discussion on the Quality Management Model of Small Dangerous Reservoir Reinforcement Project

Brief Discussion on the Reinforcement Project Scheme of A Dangerous Reservoir

Brief Discussion on the Reinforcement Project Scheme of A Dangerous Reservoir

Coordination Characteristics Analysis of Deformation between Polymer Anti-Seepage Wall and Earth Dam under Traffic Load

Polymer anti-seepage walls have been widely used in the anti-seepage reinforcement projects of earth dams. Dam crest is always supposed to meet the requirements of traffic load which has significant influence on the dam body and anti-seepage wall. In order to analyze the coordination characteristics of the deformation between polymer anti-seepage wall and dam under traffic loads, a 3D finite element model of an earth dam that considers the coupling effect of seepage field and stress field was established. Besides, the influence of load amplitude, vehicle speed and driving position on the stress and deformation characteristics of polymer anti-seepage wall and dam was analyzed, with the displacement difference between dam and wall, wall Mises stress and wall subsidence as indicators. The results show that, compared with vehicle speed, the load amplitude and vehicle speed of traffic load exerted a greater impact on the coordination characteristics of the deformation of the dam. The variation range of the displacement difference caused by axial load change reached 87.1%, while that resulted from driving position change reached 90.3%. That is, when the passing vehicle has a light axle load and passes quickly over the anti-seepage wall, it has less impact on the dam.

Ensuring the operational suitability of buildings, railways and bridges in of the Arctic zone in conditions of global warming

The effect of global warming, the trend of which in the western part of the Russian permafrost zone will be at least 2оС / 50 years is in the focus of the article. The main purpose of this study is to prevent the thawing of the permafrost base of buildings and structures of the transport infrastructure. It requires provision for strengthening the bases and foundations of objects erected according to principle I. The article provides an analysis of various reinforcement options. The elements of reinforcement (thermalstabilizers, injection wells) are shown to introduce significant thermal and deformation disturbances into the base, which requires a correct calculation justification of the reinforcement project.

Study on reinforcement methods for 0# block of long-span prestressed continuous rigid frame bridges

Long-span continuous rigid frame bridges are widely used due to their good overall performance, small deformations and good seismic properties. However, quality is difficult to guarantee during construction, which affects the bearing capacity of the bridge and the safety and durability of the structure. In order to improve the mechanical performance of continuous rigid frame bridges, the extended cross section method and the external prestressing method are discussed based on an engineering example. By comparing before and after reinforcement, the results show that the internal stresses of the reinforced structures by the two methods meet the bearing requirements. After the comparative analysis, it was concluded that the extended section method can be applied to the reinforcement of continuous rigid frame bridges under certain conditions, which can serve as a reference for other bridge reinforcement projects.

Living under threat: Will one of the last Pinna nobilis populations be able to survive?

Abstract The critically endangered fan mussel Pinna nobilis, endemic to the Mediterranean Sea, faces a drastic population decline all over the Mediterranean Sea owing to an infectious disease. Coastal lagoons represent one of this species’ last reservoirs; thus, knowledge of the population conservation status in these ecosystems is essential. An extensive monitoring programme was conducted during 2014, 2017 and 2019 in the Mar Menor lagoon, a highly eutrophicated lagoon from Spain. On average, 32,535 m2 have been surveyed each year to determine population densities, distributions and size structures. The cumulative impacts produced by intensive agriculture activity around the lagoon, together with a catastrophic meteorological phenomenon that occurred in 2019, have triggered a significant decline in fan mussel population densities and in population mean shell sizes over the years. Additionally, some fan mussels were infected by the protozoan Haplosporidium pinnae. Therefore, the current P. nobilis population from the Mar Menor is mainly composed of young individuals in specific areas that are facing an extreme situation. Urgent management and conservation actions focused on restoring the ecosystem and protecting P. nobilis individuals are urgently needed, together with reinforcement projects to increase the species’ stock in one of its last reservoirs.

Reinforcement Design and Physical Testing of New and Old Cushion Cap of Existing Bridge

As an important part of bridge structure, pile cap plays an important role in its operation. There is a lack of sufficient research in the design and construction of the existing bridges, especially in the operation process of the river crossing bridge, there will be more security risks, so it is urgent to strengthen the bearing platform. Combined with the general design theory of bridge cap, considering the feasibility of construction and the difficulty of operation, the new and old caps are planted with steel bars to make them bear the common force. Aiming at the problem of insufficient bearing capacity, the cap reinforcement method is proposed, so as to improve the stability of the bridge. The research results can provide reference for similar bridge reinforcement projects in the future.

Effects of Geosynthetic Reinforcement on Tailings Accumulation Dams

Owing to the complexity of current reinforcement mechanisms, test results from existing models alone cannot provide a basis for the design of new tailings dam reinforcement projects. On-site reinforced tailings accumulation dam testing is thus required to further understand the reinforcement mechanism. In this study, the influence of reinforcement on tailings dams and the variation law of pore water pressure (PWP) and internal pressure (IP) in the dam body after slurry discharge were analysed, and a comparative analysis was performed. The results showed that during the field test, the PWP and internal earth pressure of the accumulation dam after grouting gradually increased over time. Reinforcement can greatly reduce the PWP and IP of the reinforced dam; compared with geotextiles, the reinforcement effect of geogrids is slightly greater. Based on these results, we conclude that geosynthetics are a good choice for strengthening tailings accumulation dams.

Research and application for key technology of anti-cracking of acrylic emulsion mortar

Acrylic emulsion mortar is an ideal material of repair and reinforcement for concrete anti-carbonation and erosion, and it has been widely used in the reinforcement of culvert and sluice in recent years. When it is used, shrinkage stress occurs inside the mortar. Once this shrinkage stress exceeds the tensile strength of the mortar, cracks will appear in the mortar, which will seriously affect the construction quality and increase the repair rate or warranty workload. In this paper, the key technology of anti-cracking of acrylic emulsion mortar is studied, characteristic is analyzed of acrylic emulsion mortar protection, and various anti-cracking parameters are proposed. This key technology is verified through the application in the Dongchi sluice reinforcement project. When the technology has achieved economic benefits, it also achieved social benefits. In the future, the application prospects of the key technology of acrylic emulsion mortar anti-cracking in the culvert and sluice reinforcement project in the Yellow River Basin are very broad.

A Scan-to-BIM Methodology Applied to Stone Pavements in Archaeological Sites

The transition from Building Information Modelling (BIM) to Heritage Building Information Modelling (H-BIM) is intended to pursue an adequate knowledge of the artefact that is to be preserved, progressively replacing the traditional methods of restoration and structural reinforcement projects with new tools for the management of both existing information and new interventions. The aim of the paper is to show the application of the H-BIM method to a stone pavement road located in the Archaeological Site of Pompeii. In detail, starting from a laser scanner-based survey, juxtaposed with coordinated points georeferenced through a total station, point clouds were handled by means of several BIM-based tools to perform the road design process, starting from the digital elevation model (DEM) and proceeding to the corridor representation. Subsequently, a visual programming application based on Python language was adopted to update the corridor information by means of the object property set. As preliminary results, a tool, complete with graphical and non-graphical information, is proposed to be used in conservation, maintenance and restoration projects.

Study on Field Test and Seismic Performance of MJS Joint Microdisturbance Reinforcement on Existing Tunnel

Metro Jet System (MJS) joint microdisturbance reinforcement is often adopted to strengthen and remediate existing tunnels that are severely deformed by under-construction peripheral works, but analysis related to the reinforcement system of tunnel under consideration of seismic effects is insufficient at present. In this work, a field test of MJS joint microdisturbance reinforcement system of existing tunnels was conducted on the basis of a subway tunnel deformation reinforcement project. Then, a numerical simulation study of the seismic dynamic response of reinforcement system was performed in combination with seismic wave direction and intensity. Results show that the MJS joint microdisturbance reinforcement measures can effectively reduce the settlement and horizontal radial convergence deformation of the tunnel. The seismic longitudinal wave significantly affects the vertical displacement of the tunnel, and the seismic-induced vertical displacement of the tunnel increases with the rise in seismic intensity. The seismic transverse wave significantly affects the horizontal radial convergence deformation of the tunnel, and the seismic-induced horizontal radial convergence deformation of the tunnel increases with the rise in seismic intensity. The antiseismic property of MJS joint microdisturbance reinforcement measures on the existing tunnel is not obvious.

Discussion on the Quality and Safety of Building Structure Reinforcement Engineering

Reinforcement of building structure is the most economical and environmentally friendly method to solve the safety problems of existing building structures. However, in existing building structure reinforcement projects, due to many factors such as design, construction technology, materials, etc., various project quality problems will appear, threatening people’s lives, property safety and social stability. Therefore, we must pay attention to the quality and safety management of building structure reinforcement projects.

Study on short-term prestress loss of bridge reinforced with large diameter carbon fiber bars

At present, the technology of strengthening bridge with prestressed CFRP bars is gradually rising, so it is necessary to study the law of prestress loss. In order to evaluate the short-term prestress loss of prestressed carbon fiber reinforced (CFRP) bars, the prestress loss of CFRP bars used for reinforcement of reinforced concrete beams was studied by combining laboratory tests with practical reinforcement projects. The anchorage loss, concrete elastic compression loss of CFRP bars were obtained by measuring the prestressed loss data of CFRP bars used to strengthen retired old beams and corresponding theoretical calculation. Then, combined with the corresponding loss data of 6 prestressed CFRP bars in the actual strengthening project of Wenzhou Lijing Middle Bridge, the experimental investigation was carried out. The results show that the prestress loss of CFRP bars is between 4%∼8%, and develops rapidly in the early stage, among which the anchorage loss accounts for 45.90%. The anchorage retraction value is about 1.33mm, and the elastic compression loss of concrete is basically negligible.

Performance Optimization of Cement-Fly Ash Grouting Material Based on Response Surface Methodology

Filling grouting is effective to control the overlying strata movement and surface subsidence in mining and tunnel engineering.Grouting material is used in grouting reinforcement projects. In this experiment,based on the mechanical properties of grouting materials, Expert Design and response surface methodology (RSM) is used to optimize the mix proportion of grout materials. The sand-fly ash ratio ,water reducing agent addition are researched as variables, and the 3D response surface is established between the factors and the performance indicators. Microstructure explains the mechanism of factors affecting performance indicators.The results show the relationship between factors and performance can be well fitted by RSM.The order of significance on compressive strength and solidification ratio is sand-fly ash ratio＞water reducing agent addition and the order of significant on viscosity is water reducing agent addition＞sand-fly ash ratio.Response surface methodology accurately describes the functional relationship between the target value and the design variables.Microstructure shows hydration reaction and the secondary hydration reaction of fly ash will be carried out after cement-fly ash mixed, and the addition of fly ash is especially important for grout material properties.