scholarly journals Stability Evaluation of Deformation (Denudation) of Yuanjue Rock Cave Roof Based on Multisource Monitoring

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhigang Tao ◽  
Senlin Luo ◽  
Di Wu ◽  
Yafei Qiao ◽  
Gang Zhao ◽  
...  

The grotto rock mass is a type of cave structure, formed under the complex forces of environment, geology, and human interventions. Many scholars have carried out a lot of work in the protection of cultural relics. However, the research on detection and monitoring methods based on the parametric evolution system remains incomplete. In recent years, with the intersection and integration of disciplines, IoT (IoT: Internet of Things) systems and sensor technologies have developed rapidly. Under this background, a new monitoring system suitable for the protection of cultural relics was independently developed and applied to the protection and research work of Yuanjue rock cave, and the system was corrected and improved in practice. In this paper, according to the complex force characteristics of the sandstone roof of the Yuanjue rock cave at Dazu Rock Carvings and the geological conditions. Initially, a detailed survey of the geological conditions of the Yuanjue rock cave area was conducted; furthermore, according to the unique structural and load characteristics of the outer and inner surfaces of the roof, the monitoring methods and principles of each main control factor were explored, while the layout of monitoring points was optimized; finally, based on the microsensing technology, intelligent high-precision sensing hardware was installed and debugged for each main control factor, while the network was formed to form a multisource monitoring IoT system for the roof stability of the circular sense hole. After nearly half a year of continuous monitoring, the deformation and denudation rules of the roof of Yuanjue Cave were revealed, and a new approach of evaluating roof stability was proposed. This research provided technical support and research ideas for monitoring the stability of similar cultural relics.

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Sen Yang ◽  
Xinzhu Hua ◽  
Xiao Liu ◽  
Chen Li

To determine the impact of influencing factors on unsupported roof stability in coal mine roadway, a mechanical model of the unsupported roof was built. FLAC 3D numerical simulation was utilized to study the stability of the unsupported roof under the influence of the depth of the roadway, the thickness of the roof, and the unsupported-support distance. In view of the key influencing factors, the geological conditions of the site, and the relationship between the tensile stress and tensile strength of the unsupported roof, the maximum unsupported roof distance during roadway excavation was determined. Considering the surplus safety factor of the unsupported roof, the reasonable unsupported roof distance during the excavation of roadway 150802 was finally determined to be 2.08 m. The comprehensive roadway excavation speed increased by 62.7%, achieving a monthly progress over 500 m.


2020 ◽  
Author(s):  
Laurent Sévery ◽  
Jacek Szczerbiński ◽  
Mert Taskin ◽  
Isik Tuncay ◽  
Fernanda Brandalise Nunes ◽  
...  

The strategy of anchoring molecular catalysts on electrode surfaces combines the high selectivity and activity of molecular systems with the practicality of heterogeneous systems. The stability of molecular catalysts is, however, far less than that of traditional heterogeneous electrocatalysts, and therefore a method to easily replace anchored molecular catalysts that have degraded could make such electrosynthetic systems more attractive. Here, we apply a non-covalent “click” chemistry approach to reversibly bind molecular electrocatalysts to electrode surfaces via host-guest complexation with surface-anchored cyclodextrins. The host-guest interaction is remarkably strong and allows the flow of electrons between the electrode and the guest catalyst. Electrosynthesis in both organic and aqueous media was demonstrated on metal oxide electrodes, with stability on the order of hours. The catalytic surfaces can be recycled by controlled release of the guest from the host cavities and readsorption of fresh guest. This strategy represents a new approach to practical molecular-based catalytic systems.


Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1820
Author(s):  
Ekaterina V. Orlova

This research deals with the challenge of reducing banks’ credit risks associated with the insolvency of borrowing individuals. To solve this challenge, we propose a new approach, methodology and models for assessing individual creditworthiness, with additional data about borrowers’ digital footprints to implement comprehensive analysis and prediction of a borrower’s credit profile. We suggest a model for borrowers’ clustering based on the method of hierarchical clustering and the k-means method, which groups actual borrowers having similar creditworthiness and similar credit risks into homogeneous clusters. We also design the model for borrowers’ classification based on the stochastic gradient boosting (SGB) method, which reliably determines the cluster number and therefore the risk level for a new borrower. The developed models are the basis for decision making regarding the decision about lending value, interest rates and lending terms for each risk-homogeneous borrower’s group. The modified version of the methodology for assessing individual creditworthiness is presented, which is to reduce the credit risks and to increase the stability and profitability of financial organizations.


2019 ◽  
Vol 136 ◽  
pp. 04023
Author(s):  
Ming Zhao ◽  
Ke Li ◽  
Hong Yan Guo ◽  
KaiCheng Hua

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step.


1980 ◽  
Vol 17 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Luis E. Vallejo

A new approach to the stability analysis of thawing slopes at shallow depths, taking into consideration their structure (this being a mixture of hard crumbs of soil and a fluid matrix), is presented. The new approach explains shallow mass movements such as skin flows and tongues of bimodal flows, which usually take place on very low slope inclinations independently of excess pore water pressures or increased water content in the active layer, which are necessary conditions in the methods available to date to explain these movements.


2021 ◽  
Vol 883 ◽  
pp. 3-10
Author(s):  
Fabian Kappe ◽  
Mathias Bobbert ◽  
Gerson Meschut

The increasing use of multi-material constructions lead to a continuous increase in the use of mechanical joining techniques due to the wide range of joining possibilities as well as the high load-bearing capacities of the joints. Nevertheless, the currently rigid tool systems are not able to react to changing boundary conditions, like changing the material-geometry-combination. Therefore research work is crucial with regard to versatile joining systems. In this paper, a new approach for a versatile self-piercing riveting process considering the joining system as well as the auxiliary joining part is presented.


2018 ◽  
Vol 778 ◽  
pp. 181-186 ◽  
Author(s):  
Tayyaba Malik ◽  
Shayan Naveed ◽  
Muhammad Muneer ◽  
Mohammad Ali Mohammad

Recently, supercapacitors have attracted a tremendous amount of attention as energy-storage devices due to their high-power density, fast charge–discharge ability, excellent reversibility, and long cycling life. In this research work, we demonstrate a laser scribed super capacitor based on polyimide (PI) substrate for the storage of electrical energy. PI substrate of thickness 200μm and area 1cm × 1cm was reduced by a laser engraver with a 450 nm wavelength in the form of stackable supercapacitor electrodes. Although, PI itself exhibits non-conductive behavior; however, by laser irradiation we change the surface properties of PI and reduce its resistance. The chemical property of irradiated PI was characterized with XRD where the carbon peak was observed at 2*theta = 25.44, which confirms the reduction of PI material in to a graphene-like substance. The electrical conductivity was analyzed with a probe station and observed to be 1.6mS. Two conductive regions were assembled into a capacitor device by sandwiching a PVA/H3PO4 electrolyte in between. During the charging and discharging characterization of the capacitor device, current density was observed to be 1.5mA/cm2. Capacitance versus voltage analysis was carried out and the device showed 75mF/cm2 against a voltage sweep of ±2V. The galvanostatic charging and discharging curve shows a symmetric behavior with respect to time exhibiting the stability and durability of the device.


2017 ◽  
Vol 13 (02) ◽  
pp. 18
Author(s):  
Lei Feng ◽  
Chuang Yang ◽  
Wenbin Zheng ◽  
Ping Fu

Urban water supply pipe network is critical infrastructure for the survival of people. Efficient operation of equipment, water supply and water safety are always received great attention from the government and operators. The existing way of manual meter reading and manual inspection has the drawbacks of waste time and labor. To solve this problem, we developed databases, software platforms and mobile terminal APP (Application) based on Android operating system to integrate a remote wireless automatic meter reading system based on the existing remote wireless automatic reading meter devices which are our previous research work. The system realizes the remote monitoring of the pipe network, and it also realizes the remote control of the monitoring nodes, such as the camera shooting, selection of monitoring node's working mode and so on, which data feedback is accurate and timely, monitoring methods is simple, fast and efficient. In addition, compared to traditional methods, the system greatly reduced the manpower and resources, reduce monitoring costs. And the tests and experiments show this remote wireless automatic meter reading and control system is useful and effective.


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