arch structure
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2022 ◽  
pp. 136943322110736
Author(s):  
Shu-Yan Liu ◽  
Zhao-Yang Zhang ◽  
Xiao Xue ◽  
Qing-Zhou Wang ◽  
Cheng-Zhi Xiao

In this study, the load level, soil cover height, rise-span ratio, and arch foot constraint state were utilized to explore the mechanical properties of buried arch glass fiber reinforced plastics (GFRP) structures. Through the indoor scale-down test, the stress and deformation of arched GFRP structures under different load and soil cover height were investigated. Additionally, through the three-dimensional finite element method, the influence of the rise-span ratio and the constraint state of arch foot on the mechanical properties were obtained. The results indicate the new buried composite arch structure has excellent bearing capacity for the possible traffic load. Simultaneously, the semi-elliptical arch structure was believed to outperform the semi-circular arch structure when considering the external load. Specifically, increasing the soil cover height and reducing rise-span ratio were found to achieve the load-reduction effect.


Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 535
Author(s):  
Jianqin Wu ◽  
Jiannan Zhou ◽  
Ying Xu ◽  
Xinli Kong ◽  
Peng Wang ◽  
...  

This paper proposes a prefabricated basalt fiber reinforced polymer (BFRP) bars reinforcement of a concrete arch structure with superior performance in the field of protection engineering. To study the anti-blast performance of the shallow-buried BFRP bars concrete arch (BBCA), a multi-parameter comparative analysis was conducted employing the LS-DYNA numerical method, which was verified by the results of the field explosion experiments. By analyzing the pressure, displacement, acceleration of the arch, and the strain of the BFRP bars, the dynamic response of the arch was obtained. This study showed that BFRP bars could significantly optimize the dynamic responses of blast-loaded concrete arches. The damage of exploded BBCA was divided into five levels: no damage, slight damage, obvious damage, severe damage, and collapse. BFRP bars could effectively mitigate the degree of damage of shallow-buried underground protective arch structures under the explosive loads. According to the research results, it was feasible for BFRP bars to be used in the construction of shallow buried concrete protective arch structures, especially in the coastal environments.


2021 ◽  
Author(s):  
Dongdong Chen ◽  
Yiyi Wu ◽  
Shengrong Xie ◽  
Fangfang Guo ◽  
Fulian He ◽  
...  

Abstract Close-distance coal seams are widely distributed in China, and there is a problem of stopping mining in a large number of working faces. Taking Yanzishan mine as the engineering background, the mined-out area and the remaining end-mining coal pillar of No.4 coal seam (upper coal seam) mined in advance caused strong interference to the stopping mining of N316 working face of No.3 coal seam under it. Through field observation, laboratory experiment, and support data collection, the mechanical parameters of coal and rock mass and periodic weighting condition of the working face were mastered, and numerical simulation and similar model experiments were carried out. Three positional relationships between the stopping position of the underlying N316 working face and the upper stopping line were obtained: “externally staggered with the upper stopping line” (ESUL), “overlapped with upper stopping line” (OUL), and “internally staggered with the upper stop line” (ISUL, ISUL-SD for shorter internal staggered distances, ISUL-LD for longer ones). The formation and evolution of the stress arch structure of ESUL → OUL → ISUL-SD → ISUL-LD are obtained from the analysis: ① ESUL: there is a double stress arch structure of goaf side and end-mining coal pillar side in the overburden and stress superposition appears in the middle arch foot (stopping mining place). ② OUL: it evolved into a single arch structure of goaf-solid coal, and the stress at the stop of mining was relatively minimum. ③ ISUL-SD: it is still a single arch structure, and the stress at the stop of mining is still small. ④ ISUL-LD: the double stress arch is regenerated and stress superposition occurs at the front arch foot (stopping mining place). At the same time, the morphological evolution process of stress arch is as follows: “front and back stress arches, superimposed with middle arch foot” → “front arch gradually decreases” → “front arch dies, and two arches merge into single arch” → “single arch gradually increases” → “two arches are regenerated, superimposed with front arch foot”. On-the-spot analysis from the combination of stress and overburden structure: ① ESUL: the stress concentration degree is the highest above the stopping space, and the overburden block in the large-scale caving zone directly acts on the support, which makes the stopping operation difficult. ② OUL: although the stress environment is the best, the overlying key blocks will have hidden dangers of overall rotation or sliding instability. ③ ISUL-SD: the stress environment is good, and the overlying rock can realize the stable structure of the cantilever plate (the internal staggered distance is less than the periodic weighting step), and the mining is stopped at this position to realize the safe and smooth withdrawal of the support. ④ ISUL-LD: it is basically consistent with stopping mining when single-layer coal is used but is limited by the limited length of the end-mining coal pillar. In addition, the self-digging retracement channel is designed to serve the whole retracement process, and the idea of time-sharing partition support for a large cross-section of mining stoppage and its corresponding scheme is put forward according to the retracement process. Through the simulation of prestressed field and field practice, the roof overlying rock structure is stable during the whole retracement period, thus realizing the safe and smooth mining stoppage and retracement of the working face.


Author(s):  
Megan Balsdon ◽  
Michaela E Khan ◽  
Dillon Richards ◽  
Colin E Dombroski

BACKGROUND: Normative studies on the Arch Height Index (AHI), Arch Rigidity Index (ARI), and arch stiffness have primarily focused on healthy populations, with little consideration of pathology. The purpose of this study was to create a normative sample of the aforementioned measurements in a pathological sample and to identify relationships between arch structure measurements and pathology. METHODS: AHI was obtained bilaterally at 10% and 90% weightbearing conditions using the Arch Height Index Measurement System (AHIMS). ARI and arch stiffness were calculated using AHI measurements. Dependent t-tests compared right and left, dominant and non-dominant, and injured and non-injured limbs. Measurements of the dominant foot were compared between sexes using independent t-tests. Relationships between arch stiffness and age, sex, and AHI were examined using the coefficient of determination (R2). One-way ANOVAs were used to determine differences between arch structure measurements and number of pathologies or BMI. RESULTS: A total of 110 participants reported either one (n=55), two (n=38), or three or more (n=17) pathologies. Plantar fasciitis (n=31) and hallux valgus (n=28) were the most commonly reported primary concerns. AHI, ARI, and arch stiffness did not differ between limbs for any comparisons, nor between sexes. Between subgroups of BMI and number of pathologies, no differences exist in AHI or ARI; however, BMI was found to have an impact on AHI (10%WB) and arch stiffness (p<.05). Arch stiffness showed a weak relationship to AHI, where a higher AHI was associated with a stiffer arch (R2=0.06). CONCLUSIONS: Normative AHI, ARI and arch stiffness values were established in a pathological sample with a large incidence of plantar fasciitis and hallux valgus. Findings suggest relationships between arch stiffness and both BMI and arch height; however, few trends were noted in AHI and ARI. Determining relationships between arch structure and pathology is helpful for both clinicians and researchers.


2021 ◽  
Vol 17 (2) ◽  
pp. 158-168
Author(s):  
Frederikus Dianpratama Ndouk ◽  
Mauritius IR Naikofi ◽  
Krisantos Ria Bela ◽  
Don Gaspar Noesaku Da Costa

So far, the system of the roof structure of residential and office buildings is dominated by conventional frame types. The use of a 3-joint arch structure system is only familiar to warehouse buildings and the like. The purpose of this study is to identify the feasibility of using type 3 joint arches on the roof of a residential building. The research scenario is focused on calculations using SNI 7973-2013, namely Design Specifications for Wooden Construction and Specific Static Structural Analysis Methods for 3 Joint Arch Structures based on the length of the truss span model, which is 9 m. The calculation result indicates that 1). The 3-joint curve type is worth using as it proves stable and safe 2). The distance between the truss of the roof truss affects the dimensions of the truss. The implication is that the construction of the roof of a residential house can use a 3-joint arch structure system while the basic material for modeling uses Code E20 wood material with Quality B, depending on the length of the span and the slope of the roof.  


2021 ◽  
Vol 14 (18) ◽  
Author(s):  
Xiaoping Shao ◽  
Long Wang ◽  
Xin Li ◽  
Zhiyu Fang ◽  
Bingchao Zhao ◽  
...  

AbstractStrip mining is the key technology to solve the problem of coal mining under water, so mastering the law of overburden load transfer in strip mining is the key to safe production in working face. We studied it in the context of the shallow seam No. 3 in the Shanghe Coal Mine (northern Shaanxi Province, China) through similarity simulation and field measurement analysis. A theoretical analysis, based on the concept of pressure arch, allowed the establishment of a continuous arch theoretical model for the strip coal pillars (or filling bodies) of the mine. A similar simulation study on strip filling and staged mining has previously shown that, in a first stage, the overlying strata load is mainly transferred to the remaining strip coal pillars; in a second stage, this load is mainly sustained by the odd-numbered strip coal pillars; finally, in a third stage, this load is mainly sustained by the first-stage strip filling body, while the third-stage filling body is not loaded. Our theoretical analysis showed that, during the first stage, the overlying rock load outside the arch was mainly sustained by the arch structure, while that inside of the arch was sustained by the filling body; in the second stage, the arch structure lost stability during the recovery of the even-numbered coal pillars and the arch axis developed upward, leading to the formation of a new arch with an odd number of coal pillars as the arch foot; in the third stage, after the recovery of the odd-numbered coal pillars, a new arch was formed. The arch foot of the new supporting structure was represented by the first-stage filling body; moreover, the load was mainly borne by the second-stage filling body, ensuring the stability of the overburden rock after mining. The theoretical analysis revealed that the pillar or filling body only bears part of the overburden load in strip filling mining. The pillar (filling body) load in correspondence of working face 3216 during each stage of filling was measured and analyzed, proving a continuous arch structure transformation between the pillar and the filling body. Finally, we verified the reliability of the proposed theoretical model.


2021 ◽  
Author(s):  
Yingming Yang ◽  
Hengzhong Zhu ◽  
Quansheng Li ◽  
Kai Zhang ◽  
Yongqiang Zhao

Abstract Traditionally, the study on the bearing structure of overlying strata mainly focuses on bedrock with the effect of the overlying unconsolidated layer. It simply considered as uniformly loading on the top interface of the bedrock, and ignores the bearing structure for unconsolidated layer. Combined with the geological conditions of shallow burial thick unconsolidated layer in Shendong mining area,the mechanical model of the arch structure for the unconsolidated layers was established. The relationship between the arch height and span was analyzed with theoretical formula and the dynamic evolution mechanism of arch structure was studied with numerical simulation. Besides, formula of arch structure ultimate height was derived. The influence mechanism of arch structure on ground fissures was revealed and criterion was obtained, which was verified by field monitoring data. Furthermore, a classification method of arch structure in thick unconsolidated layers was proposed.


2021 ◽  
Vol 1972 (1) ◽  
pp. 012131
Author(s):  
Chen Zhuo ◽  
Sun Huixiang ◽  
Yuan Yingjie

2021 ◽  
Vol 11 (13) ◽  
pp. 5862
Author(s):  
Jorge Pérez-Aracil ◽  
Carlos Camacho-Gómez ◽  
Alejandro Mateo Hernández-Díaz ◽  
Emiliano Pereira ◽  
Sancho Salcedo-Sanz

In this paper, a novel procedure for optimal design of geometrically nonlinear submerged arches is proposed. It is based on the Coral Reefs Optimization with Substrate Layers algorithm, a multi-method ensemble evolutionary approach for solving optimization problems. A novel arch shape parameterization is combined with the Coral Reefs Optimization with Substrate Layers algorithm. This new parameterization allows considering geometrical parameters in the design process, in addition to the reduction of the bending moment carried out by the classical design approach. The importance of considering the second-order behaviour of the arch structure is shown by different numerical experiments. Moreover, it is shown that the use of Coral Reefs Optimization with Substrate Layers algorithm leads to nearly-optimal solutions, ensuring the stability of the structure, reducing the maximum absolute bending moment value, and complying with the serviceability structural restrictions.


2021 ◽  
Author(s):  
Guangbo Chen ◽  
Pengcheng Teng ◽  
Huiqiang Duan ◽  
Guohua Zhang ◽  
Tan Li

Abstract After the coal mine disaster, the collapsed accumulation body blocked the roadway and interrupted the rescue route, which seriously affected the development of rescue. Based on the post-disaster blockage rescue route of the collapsed accumulation body, the morphology and structural characteristics of the accumulation body were analyzed, and the process of excavating the rescue channel in the collapsed accumulation body in the mining roadway was simulated using CDEM software, and the moving mode of accumulation body fragments was discussed. The study found that: the formation of the accumulation body is the process of continuous “self-organization” adjustment of the rock fragments; the accumulation body along the direction of the roadway axis is divided into three areas: pre-sorting accumulation area, post-sorting accumulation area, and non-sorting accumulation area; the particle size of the accumulation body-particle content conforms to the normal distribution; the harder the rock fragments constituting the accumulation body is, the particle size of the fragments is more different; the number of contact points of the fragments of the tightly accumulation body is more than that of the loose accumulation body; the excavation of the rescue channel is accompanied by the random “self-organization” movement of the accumulated body; the settlement and deformation of the accumulated body is actually the continuous collapse of the old arch structure, and the process of continuous formation of a new arch structure; the initial force of the rescue channel excavation is small, then it increases sharply, and finally stabilizes; the fragment adjustment forms are mainly divided into horizontal movement adjustment, vertical movement adjustment, rotation movement adjustment, and multi-directional movement adjustment. The research conclusion has certain guiding significance for the rescue channel excavation under the condition that the collapsed accumulation body blocks the roadway after the coal mine disaster.


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