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1.
Sensors (Basel) ; 22(10)2022 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-35632040

RESUMEN

For measuring and region-identifying the deep displacement of slopes, a rod-fiber coupling structure based on optical time-domain reflection technology was designed. Accuracy of measurement and region identification in the deep displacement of slopes were studied by calibration experiment and model experiment. A rod-fiber coupling structure was able to calculate the variation and accurately identify the region of deep displacement of a slope compared with the measured downslide displacement of the slope model. The maximum measurement error of the deep displacement of the slope was 10.1%, the identification error of the displacement region was less than 4.4%, and the accuracy of the displacement-region identification of the rod-fiber coupling structure was 3.1 cm. Thus, the rod-fiber coupling structure based on optical time-domain reflection technology can be used for measuring and for region identification in the deep displacement of the slopes, and can provide a new method for the identification of the sliding surfaces of slopes.

2.
Sensors (Basel) ; 22(21)2022 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-36365815

RESUMEN

The mechanical performance analysis of the members is the primary basis for evaluating the hoisting quality and safety of the valve hall grid structure. Ordinarily, manual analysis of monitoring data and on-site experience inspection are employed to structural judgment, but it is challenging to evaluate the correlation of the various members and the overall safety of a valve hall. In this paper, an intelligent correlation real-time analysis method based on a BPNN (Back Propagation Neural Network) for the mechanical properties of members is proposed to intelligently control the safety of valve hall grid structure hoisting. The correlation between the mechanical properties of multi-points in the grid structure is used to model the target measuring points. In addition, an intelligent real-time analysis system is used to manage and apply the mechanical property correlation and abnormality of members in real-time. Then, the model is applied to a super-span valve hall in South China, and the application effect is good. The mechanical property correlation model can accurately reflect the mechanical state of the valve hall grid structure hoisting process. Simultaneously, it can effectively pinpoint hidden dangers and locate risk members. It provides a new reference for the normal operation and maintenance of a super-span valve hall grid.

3.
Sensors (Basel) ; 21(14)2021 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-34300477

RESUMEN

In the process of using a long-span converter station steel structure, engineering disasters can easily occur. Structural monitoring is an important method to reduce hoisting risk. In previous engineering cases, the structural monitoring of long-span converter station steel structure hoisting is rare. Thus, no relevant hoisting experience can be referenced. Traditional monitoring methods have a small scope of application, making it difficult to coordinate monitoring and construction control. In the monitoring process, many problems arise, such as complicated installation processes, large-scale data processing, and large-scale installation errors. With a real-time structural monitoring system, the mechanical changes in the long-span converter station steel structure during the hoisting process can be monitored in real-time in order to achieve real-time warning of engineering disasters, timely identification of engineering issues, and allow for rapid decision-making, thus avoiding the occurrence of engineering disasters. Based on this concept, automatic monitoring and manual measurement of the mechanical changes in the longest long-span converter station steel structure in the world is carried out, and the monitoring results were compared with the corresponding numerical simulation results in order to develop a real-time structural monitoring system for the whole long-span converter station steel structure's multi-point lifting process. This approach collects the monitoring data and outputs the deflection, stress, strain, wind force, and temperature of the long-span converter station steel structure in real-time, enabling real-time monitoring to ensure the safety of the lifting process. This research offers a new method and basis for the structural monitoring of the multi-point hoisting of a long-span converter station steel structure.


Asunto(s)
Desastres , Acero
4.
Sensors (Basel) ; 19(13)2019 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-31252536

RESUMEN

The long-term structural performance of underground structures in reclamation areas is very sensitive to the vibrations caused by vehicles passing above the structures and environmental factors (e.g., tide levels, rainfall and temperature). In the present study, an integrated remote real-time structural health monitoring system using fiber Bragg grating sensors was developed to assess the structural performance of underground structures. Using a composite road box-type structure project in a reclamation area in Southern China as a case study, the developed real-time system was implemented to investigate the effects of changes in tide levels, rainfall, temperature and vehicle induced vibrations on crack propagation in the structure. The results show that the change in tide levels has little influence on the change in crack width in the structure, whereas variations in temperature could significantly influence the crack width with an average Pearson correlation of around 0.8. In addition, the crack width generally decreases with an increase in rainfall. Furthermore, a relatively low frequency (<25 Hz) induced by the traffic could result in a relatively larger crack width.

5.
Sensors (Basel) ; 18(9)2018 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-30135394

RESUMEN

Monitoring the internal force of the rocks surrounding a mine-shield tunnel for the initial support of a mine-shield tunnel, in complex geological and hydrological environments, requires bolts with specific features such as high tensile strength, low shear strength, good insulation and resistance to corrosion. As such, internal force monitoring has become an important issue in safety monitoring for such tunneling projects. In this paper, the adaptability of a mine-shield tunnel project in a corrosive environment is investigated. A fiberglass reinforced plastic (FRP) bolt with high tensile strength, low shear strength, resistance to fatigue, non-conductivity and resistance to corrosion is used as a probe in tandem with an anchor-head dynamometer to monitor the internal force of the rocks surrounding a mine-shield tunnel for initial support. Additionally, solar energy collection technology is introduced to create a remote monitoring system. Using a 2.5 km long railway tunnel located in the northeast of the Pearl River Delta of China as a case study, the present study shows that, compared with a conventional steel bolt, the FRP bolt has advantages, such as avoidance of the risks associated with the shield machine, insulation and resistance to corrosion. As a probe, the response of the FRP bolt to events such as a blasting vibration and a construction disturbance that results in internal changes in the surrounding rock demonstrates a clear pattern that is appropriate for monitoring the internal force of the rocks surrounding a mine-shield tunnel in a corrosive environment. FRP bolt-based monitoring not only provides new technological support for controlling the risk involved in the initial support of a mine-shield tunnel but can also be widely deployed in projects with special requirements for disassembly, conductivity and corrosion.

6.
PLoS One ; 19(5): e0300805, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38820410

RESUMEN

3D stratum roaming can visualize the complex geomorphology, underground structure and stratum distribution of geotechnical engineering. Conventional 3D stratum roaming technology is generally aimed at roaming outside the 3D stratum model but rarely roams inside the 3D stratum model, and the efficiency of switching between external and internal roaming is low. In practical engineering, especially in geological and geotechnical engineering, the underground structure and stratum situation are critical. Therefore, focusing on this problem, this paper adopts a three-dimensional roaming engine to connect the inside and outside of a three-dimensional model. Based on an internal and external boundary identification method, the combination of external roaming and internal roaming of the three-dimensional stratum model is implemented by using a stratum virtual surface, and lightweight loading is carried out by controlling the stratum virtual surface to establish the internal and external roaming of the 3D stratum model, and to give full play to the advantages of lightweight loading to provide more intuitive and comprehensive geological information for the project.


Asunto(s)
Modelos Teóricos , Imagenología Tridimensional/métodos , Geología/métodos
7.
Sci Rep ; 14(1): 20168, 2024 08 30.
Artículo en Inglés | MEDLINE | ID: mdl-39215113

RESUMEN

The utilization of high-performance ester materials in addressing soil erosion and conserving water remains a crucial area of research in soil remediation. Currently, however, the mechanism underlying the role of these materials in vegetation restoration remains unclear, hampering the accurate determination of the optimal ratio of high-performance ester composite materials for soil enhancement. To address this issue, this study examines the mechanism of how high-performance ester composite materials affect the germination and growth of plant seeds through soilless cultivation experiments. The results revealed that the high-performance ester composite materials significantly enhanced seed germination ability and fostered plant seedling growth. Notably, the promotional effects of the ester adhesive and water-retaining materials within the high-performance ester composite varied. Specifically, the adhesive material significantly spurred radicle development, while the water-retaining material significantly accelerated germ growth. Varying concentrations of adhesive materials exerted distinct effects on plant growth. In particular, a small amount of adhesive materials enhanced seed germination, whereas excessive amounts exhibited inhibitory effects. Consequently, the optimal adhesive materials dosage conducive to plant growth and the optimal weight ratio of adhesive to water-retaining materials were ascertained. Additionally, the underlying mechanism of high-performance ester composite materials influence plant growth was elucidated. Overall, this research offers a theoretical foundation for the optimal ratio adjustment of high-performance ester composite materials to optimize soil improvement efforts.


Asunto(s)
Ésteres , Germinación , Semillas , Suelo , Germinación/efectos de los fármacos , Suelo/química , Ésteres/química , Semillas/crecimiento & desarrollo , Semillas/efectos de los fármacos , Plantones/crecimiento & desarrollo , Plantones/efectos de los fármacos , Desarrollo de la Planta/efectos de los fármacos , Agua/química , Adhesivos/química
8.
PLoS One ; 19(10): e0310172, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39352922

RESUMEN

Red bed composite polymers composed of weathered red bed soil, adhesive materials, and water-retaining materials have been applied as a new type of material for environmental restoration. However, the promotion and application of this material has been limited by a lack of understanding of its action mechanism in environmental restoration. The objective of this study is to innovatively propose a water‒soil-air‒plant mutual feedback mechanism based on this material. Therefore, water‒soil-air‒plant mutual feedback tests were conducted in this study under 3 initial water contents and 10 red bed composite polymers ratios. Key parameters, namely, water content, soil conductivity, pH, temperature, O2 and CO2 contents, pigeon pea (Cajanus cajan) germination number and plant height were monitored and analyzed. As the results, a mutual feedback mechanism driving water retention, soil consolidation, air retention, and plant rooting was revealed under the application of red bed composite polymers. And, suitable environments and optimal compositions for this material are proposed. The study results provide a theoretical basis for the large-scale application of red bed composite polymers.


Asunto(s)
Polímeros , Suelo , Agua , Suelo/química , Agua/química , Polímeros/química , Aire , Temperatura , Concentración de Iones de Hidrógeno , Germinación , Restauración y Remediación Ambiental/métodos , Dióxido de Carbono/metabolismo , Dióxido de Carbono/análisis
9.
IDCases ; 36: e01970, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38681082

RESUMEN

A 30-year-old man presented to otolaryngology department complaining of nasal congestion and runny nose for six months, with repeated fever, and shortness of breath.The weight loss in the past 20 days was about 5 kg. At first, he was diagnosed with respiratory infection and was treated with antibiotics, but it didn't work. Nasopharynx CT scan showed soft tissue thickening without bone destruction, with obvious inhomogeneous enhancement. Chest CT scan revealed multiple patchy clouding nodules and ground-glass opacity with poorly-defined border. Urine test showed urine microalbumin ≥ 150 mg per liter (reference range, 0-20), white-cell count of 11.0 cells per microliter (reference range, 0-5). Histology of nasopharynx biopsy showed small-medium-vessel necrotizing vasulitis.Although nasopharyngeal histopathology didn't reveal peri- and extravascular granulomatosis and antineutrophilic cytoplasmic antibodies (ANCA) was negtive, he had ENT signs, lung nodules, and kidney involvement and condition developed fast and biopsy showed small- and- medium-vessel vasculitis. Therefore, the patient met the classification criteria for GPA and his symptoms were disappeared 1 week after starting GPA treatment, the chest CT showed ground-glass opacity decreased and CRP、ESR became normal. He was treated with rituximab combined with glucocorticoids for 4 weeks, after which he was discharged.

10.
PLoS One ; 19(4): e0299323, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38568981

RESUMEN

Ester materials have become a significant topic in ecological restoration because of their degradability and lack of pollution. However, these artificial materials have issues such as high resource consumption and high cost. Therefore, finding a scientific substitute for ester materials is crucial to reduce costs. This study proposes the use of weathered red-bed soil to partially replace ester materials. Orthogonal coupled compounding and ecological effect tests were performed to analyze the soil improvement mechanism based on the mineral composition, soil structure, and electrical conductivity properties of the weathered red-bed soil. The experimental findings indicated that the soil modified using ester materials exhibited improved strength, water retention, and aeration owing to changes in the soil structure. Plant germination and height increased by 55% and 37 mm, respectively, when using a ratio of 15 g/m2 absorbent ester material, 2.5 g/m2 adhesive ester material, and 5% weathered red-bed soil. Through this approach, the amount of ester material to be used could be further reduced by 75%. The weathered red-bed soil offers improved ecological effects by altering the physical, mechanical, and hydraulic properties of the soil structure. This study presents a theoretical foundation for ecological conservation using weathered red-bed soil as a substitute for certain ester materials.


Asunto(s)
Suelo , Tiempo (Meteorología) , Suelo/química , Plantas
11.
Zhongguo Zhong Xi Yi Jie He Za Zhi ; 33(10): 1309-14, 2013 Oct.
Artículo en Zh | MEDLINE | ID: mdl-24432669

RESUMEN

OBJECTIVE: To evaluate the curative effect and safety of Bushen Qiangji Decoction (BQD) and Qingre Qiangji Decoction (QQD) in treating ankylosing spondylitis (AS) patients, and to verify the clinical utility of AS syndrome differentiation and treatment scheme [Shen-deficiency induced stasis obstruction syndrome (SDISOS) and dampness-heat obstruction syndrome (DHOS) being two basic syndrome types, Shen invigorating blood activating method (SIBAM) and heat clearing dampness resolving method (HCDRM) being two basic treatment methods]. METHODS: Totally 354 AS patients of SDISOS and DHOS were randomly assigned to the treatment group and the control group using a multi-center randomized, positive drug parallel-controlled clinical trail. Patients in treatment group were treated by BQD or QQD according to syndrome typing, while those in the control group took Sulfasalazine enteric-coated tablet (SECT), 24 weeks as one therapeutic course. After treatment, the clinical efficacy was evaluated by using ASAS20 standard (set by Asessment in Ankylosing Spondylitis working group), Chinese medical efficacy evaluation standards, and BASDAI, BASFI, BASMI, night-pain index, spinal pain index, PGA, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). RESULTS: After 24 weeks of treatment by BQD or QQD, ASAS20 standard rate was 86.75% in the treatment group, and the total effective rate of Chinese medical syndrome was 85.47%. They could significantly reduce patients' integrals of Chinese medical syndrome, BASDAI, BASFI, BASMI, night-pain index, spinal pain index, and PGA (all P < 0.01). CONCLUSIONS: QQD and BQD got confirmable clinical effects in treating AS, providing strong evidence of evidence-based medicine for syndrome differentiation and treatment of AS.


Asunto(s)
Medicamentos Herbarios Chinos/uso terapéutico , Fitoterapia/métodos , Espondilitis Anquilosante/tratamiento farmacológico , Adolescente , Adulto , Femenino , Humanos , Masculino , Medicina Tradicional China , Persona de Mediana Edad , Resultado del Tratamiento , Adulto Joven
12.
PLoS One ; 18(6): e0286949, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37289840

RESUMEN

Ecological slope protection projects (such as the reinforcement of low slopes by plants and ecological restorations of the soil of high steep rocky slopes) are essential for restoring the natural environment. In this study, red bed soil and composite polymer adhesive materials were used to develop an ecological membrane for application in slope ecological protection. The basic physical and mechanical properties of the ecological membranes with different material percentages were studied through tensile strength test and viscosity test, the effect of different material percentages on the properties of ecological membranes was studied, and the soil protection performance and ecological restoration performance were studied through anti-erosion and plant growth tests. The results show that the ecological membrane is soft and tough, with high tensile strength. The addition of the red bed soil can enhance the strength of the ecological membrane, and the ecological membrane with 30% red bed soil has the highest tensile strength. The ecological membrane has considerable tensile deformation capability and viscosity, and up to 100% by mass, the more composite polymer adhesive materials added, the greater the tensile deformation capability and viscosity. And the ecological membrane can enhance the anti-erosion performance of the soil. This study clarifies the development and technology of the ecological membrane, reveals the effect of different material percentages on the properties of ecological membrane, and analyzes the slope ecological protection mechanism of the ecological membrane, thereby providing theoretical and data support for its development, improvement, and application.


Asunto(s)
Ambiente , Suelo , Adhesivos , Plantas , Polímeros
13.
PLoS One ; 17(10): e0275867, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36215290

RESUMEN

Mulching film is an important material in ecological restoration, such as desert control, saline alkali land improvement, and slope greening protection. At present, both solid and liquid mulching films are mainly made of man-made materials, which have a great impact on the ecological environment and are expensive. Naturally weathered red-bed soil mud films are being applied in the construction industry because of their advantages of environmental friendliness and low cost. However, at present, film formation needs to occur under pressure, in complex processes, which results in great application limitations, so it is difficult to popularize and apply these natural mud films to the field of ecological restoration. Therefore, exploring high-quality film formation under pressureless conditions is key for the application of naturally weathered red-bed soil mud films in the field of ecological restoration. To solve this problem, this paper takes naturally weathered red-bed soil, without additives; designs and carries out mud film-forming tests of naturally weathered red-bed soil and a comparison test with bentonite under pressureless conditions; tests the influence of mud particle gradation, viscosity and moisture content on the film-forming effect; optimizes the mud film-forming ratio; and further studies the thickness, water resistance, compression resistance. Acid and alkali resistances are tested and compared with international standards. The results show that the naturally weathered red-bed soil can form a mud film under pressureless conditions. The optimal (high-quality) film corresponds to a mud viscosity of 29.6-52.6 Pa·s, water content of 15-35%, and content of particles with particle sizes smaller than 1 mm of 75%-85%. Compared with international standards and bentonite, the naturally weathered red-bed soil mud film meets the ecological restoration standard, has a better water resistance, compression resistance, and acid and alkali resistances than bentonite mud film, and has the advantages of a wide distribution, low cost, simple sample preparation and wide application range. Therefore, weathered red-bed soil mud film is a film technology with obvious comparative advantages that can be introduced into the field of ecological restoration and has broad prospects.


Asunto(s)
Contaminantes del Suelo , Suelo , Álcalis , Bentonita , Humanos , Contaminantes del Suelo/análisis , Agua , Tiempo (Meteorología)
14.
Artículo en Inglés | MEDLINE | ID: mdl-36011564

RESUMEN

Plant-based ecological protection is one of the effective methods to improve the stability of slope soils. However, plants need a stable growth environment and water supply. Although it has been demonstrated that polymer materials can effectively enhance the stability and water retention of soils, their improvement mechanism and long-term effects are yet to be clear. In this paper, we use a new polymer composite material (ADNB), an optimized compound of nano-aqueous binder (NAB) and super absorption resin (SAR), to conduct outdoor model tests to study the effects of different ADNB ratios on soil compactness, biochemical properties, and plant growth at longer time scales, and to explore its action law and mechanism of enhancing the ecological self-repairing ability of surface slope soil. The results show that ADNB can effectively improve the soil structure, increase the compactness of the soil, increase the organic matter content, microbial population and available nutrient content in the soil, thus promoting plant growth. The adsorption and agglomeration effect of the NAB in ADNB on soil particles and its degradation in natural environment can be observed by SEM. In summary, ADNB can not only effectively enhance the ecological self-repairing ability of surface slope soil, but also has good environmental friendliness and can be completely degraded under natural conditions without additional adverse effects on soil and environment.


Asunto(s)
Contaminantes del Suelo , Suelo , Plantas/metabolismo , Polímeros , Suelo/química , Contaminantes del Suelo/análisis , Agua/metabolismo , Abastecimiento de Agua
15.
Artículo en Inglés | MEDLINE | ID: mdl-36231420

RESUMEN

Sprayed planting concrete (SPC) can be used for the ecological restoration of rocky steep slopes. It is a kind of outside-soil material with excellent soil and slope stabilization performance, and plants can grow in SPC, thus achieving harmony between engineering stability and ecological restoration and improving the landscape and ecosystem. The addition of cement is the key to allowing SPC to achieve slope stabilization and prevent soil erosion. However, the addition of cement can cause SPC to have high alkalinity, overheating (cement generates hydration heat), and excessive hardening, which are not conducive to the growth of plants and can lead to poor ecological performance of SPC for slope ecological restoration. We studied the improvement of the ecological performance of SPC by using a polymer composite material composed of a polymer adhesive material and a polymer water-retaining material. This paper studied the improvement effects of the polymer composite material on the ecological performance of SPC used in slope ecological restoration through a laboratory erosion resistance test and a plant growth test. The results showed that SPC with the addition of polymer composite material can reduce its cement content by about 50% while still retaining excellent erosion resistance performance when it is used in slope ecological restoration. Additionally, the plant germination rates and plant heights when using the SPC improved by polymer composite material were increased by 190% and 110%, respectively. These results show that polymer composite material can significantly improve the ecological performance of SPC and effectively improve its slope ecological restoration effects. This study provides theoretical and technical support for the application of SPC in ecological restoration on rocky steep slopes.


Asunto(s)
Ecosistema , Polímeros , Plantas , Suelo , Agua
16.
Polymers (Basel) ; 14(16)2022 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-36015622

RESUMEN

Chemical sand-fixing technology has shown good potential in preventing desertification, but the effect is determined by materials. In this paper, the adsorption behavior of quartz and six common polymer sand-fixing agents under dry conditions was studied by molecular dynamics method. The results show that all polymers could be adsorbed on the surface of quartz and their functional groups play an important role in the adsorption process. Compared with other materials, the binding energy and the number of hydrogen bonds of PAA-quartz composites were improved by 30.7-65.6% and 8.3-333.3%, respectively. It was found that the number of hydrogen bonds formed under the unit molecular was positively correlated with the mechanical properties of the improved sandy soil. This study provides an accurate, efficient and inexpensive qualitative evaluation method for the curing effect of sand fixers, which will assist in the screening and development of new high performance sand fixers.

17.
Sci Rep ; 12(1): 14711, 2022 08 29.
Artículo en Inglés | MEDLINE | ID: mdl-36038760

RESUMEN

The loose structure and low mechanical strength of the surface soil make it vulnerable to damage under erosion conditions. Slope ecological protection is one of the effective methods to improve the stability of slope soil. Although it has been proved that polymer modified materials can effectively improve the soil properties and the environmental protection effect of slope, so far, the improvement mechanism has not been fully understood, especially the chemical mechanism of the material on the enhancement of soil mechanical properties is not clear. In the present study, the effects of nano-aqueous adhesive (NAA) on unconfined compressive strength, shear strength and aggregate characteristics of soil were studied by a series of laboratory experiments. The results show that NAA can increase the strength, aggregate number and stability of the soil, to effectively improve the stability of surface soil. In addition, through infrared spectroscopy and SEM test, it was found that NAA molecules were mainly distributed in the interlayer position of flaky clay minerals, mainly connected with clay minerals through hydrogen bonds, thereby effectively enhancing the cohesion of soil particles.


Asunto(s)
Adhesivos , Suelo , Arcilla , Conservación de los Recursos Naturales/métodos , Minerales , Suelo/química , Agua
18.
PLoS One ; 17(9): e0275034, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36178931

RESUMEN

Studying the constitutive relation of soft clays is of critical importance for fundamentally understanding their complex consolidation behavior. This study proposes a fractional differential constitutive model in conjunction with an intelligent displacement inversion method based on the classic particle swarm optimization for modeling the deformation behavior of soft clay. The model considered the rheological properties of soft clay at different consolidation stages. In addition, statistical adaptive dynamic particle swarm optimization-least squares support vector machines were implemented to identify the model parameters efficiently. The accuracy and effectiveness of the model were validated using available experimental results. Finally, the application results showed that the proposed model could efficiently simulate coupling properties of soft clay's primary and secondary consolidations.


Asunto(s)
Inteligencia , Máquina de Vectores de Soporte , Arcilla , Análisis de los Mínimos Cuadrados , Reología
19.
PLoS One ; 16(6): e0252733, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34086794

RESUMEN

Shield tunneling in karst areas poses significant challenges, as vibration caused by the shield machine can disturb the stability of the karst caves, ultimately resulting in the collapse of a tunnel. In the present study, a numerical model involving an iteration process was developed based on the Mindlin solution scheme to identify the optimal shield tunneling speed for minimizing the disturbance to karst cave stability. The developed model was then implemented to investigate an underground tunnel constructed in a karst region with different shield tunneling strategies. By using the variation in the energy density of a karst cave as a performance index, the model predicts that when approaching the affected zone of a karst carve (e.g., approximately 5 m from the carve), the shield tunneling machine should be controlled within a certain speed (i.e., < 30 mm/min). Once the shield tunneling machine moves into the affected zone of the cave, the speed of the machine needs to be decelerated to 11 mm/min, and the speed of 30 mm/min can be restored when the shield machine moves out of the affected zone. This finding demonstrates that the developed model could potentially be used to identify the optimal shield tunneling speed to minimize the disturbance to karst cave stability and ensure the safety of tunnel construction in karst regions.


Asunto(s)
Cuevas , Agua Subterránea
20.
PLoS One ; 16(8): e0256190, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34398920

RESUMEN

The geosynthetic-reinforced pile-supported embankment (GRPSE) system has been widely used in road construction on soft soil. However, the application of the GRPSE system is often restricted by its high-cost. The reason is that they are designed for bearing control as defined in the past. During the construction process, the pile spacing is reduced to meet the requirements for the embankment bearing capacity and settlement. These factors cause the membrane effect to not be exploited. As a result, the utilization efficiency of the bearing capacity of the soil between the piles is low and the project cost is high. Therefore, in order to solve the problem of insufficient bearing capacity of soil between piles, we established a settlement calculation model of soil between piles based on membrane effect. The model considers the relationship between the geosynthetic reinforcement (GR) and the pile spacing. Based on the obtained model, a method for optimizing the soil bearing capacity of GRPSEs is proposed. By controlling the settlement of soil between piles, the bearing capacity of soil between piles and the membrane effect of embankment can be fully utilized. Therefore, the project cost can be reduced. Finally, the method is applied to field tests for comparison. The results show that the method is reasonable and applicable. This method can effectively exploit the membrane effect and improve the utilization efficiency of the bearing capacity of the soil between piles. An economical and reasonable arrangement scheme for the piles and GR was obtained. This scheme can not only ensure the safety of the project, but also fully utilize the bearing capacity of the soil between the piles and provide a new method for engineering design.


Asunto(s)
Industria de la Construcción/métodos , Suelo/química , Humanos , Modelos Estadísticos
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