Deformation Of Supporting Structure Research Articles

Observed Characterization of Multi‑level Retaining Structure for Deep Excavation of Subway Station

Traditional support structures cannot meet the complex conditions of different excavation depths and areas in underground transportation hubs. On the basis of fully considering the spatial position relationship of foundation pit groups, this article proposes a multilevel retaining system that meets the requirements of multilevel foundation pit excavation. The evolution law of the support structure during the excavation process of the inner pit was explored using on-site monitoring and numerical simulation methods. The results indicate that the excavation of the inner pit reduces the passive earth pressure, and the deformation of the outer support structure can be effectively suppressed by setting a retaining structure or a bottom slab in the bench zone. The excavation of the inner pit causes significant vertical deformation of the support structure adjacent to the foundation pit, while the impact on the structure far away from the foundation pit is relatively small. According to the contact force chain and soil pressure between the two rows of support structure, the soil in this area is divided into a “relaxation zone” and a “compression zone.” The evolution mechanism of earth pressure in the case of mutual-effect failure between two rows of piles is revealed. This paper addresses the deformation properties of multilevel support structures as well as the mechanism of earth pressure evolution between structures.

An Online Measurement and Calibration Method for a Radio Telescope Sub-Reflector Support Structure Using Fiber Bragg Grating.

The position and altitude of a sub-reflector have an important influence on the pointing accuracy of a radio telescope. With the increase of the antenna aperture, the stiffness of the support structure for the sub-reflector decreases. This causes deformation of the support structure when environmental loads, such as gravity, temperature, and wind load, are applied to the sub-reflector, which will seriously influence antenna pointing accuracy. This paper proposes an online measurement and calibration method for assessing the deformation of the sub-reflector support structure based on the Fiber Bragg Grating (FBG) sensors. Firstly, a reconstruction model between the strain measurements and the deformation displacements of a sub-reflector support structure is established based on the inverse finite element method (iFEM). In addition, a temperature-compensating device with an FBG sensor is designed to eliminate the effects of temperature variations on strain measurements. Considering the lack of the trained original correction, a non-uniform rational B spline (NURBS) curve is built to extend the sample data set. Next, a self-structuring fuzzy network (SSFN) is designed for calibrating the reconstruction model, which can further improve the displacement reconstruction accuracy of the support structure. Finally, a full-day experiment was carried out using a sub-reflector support model to verify the effectiveness of the proposed method.

Studying deformation of support horizontal steel tank when performing a frequency analysis

The article is devoted to the study of deformation of support structure of horizontal steel tank, which is located in the North of Tyumen region. This study was carried when performing frequency analysis. It is found that the hardness ring was great deformation when performing frequency analysis of support structure of horizontal steel tank. The support structure of tank has lost its balance, but retained its integrity.

Texture/phase evolution during plasma treatment of microwave-combustion synthesized KOH/Ca12Al14O33-C nanocatalyst for reusability enhancement in conversion of canola oil to biodiesel

Glow-discharge plasma was utilized for treating the KOH/carbonated calcium aluminate synthesized by MCM. Treated and untreated nanocatalysts were characterized by XRD, FESEM, EDX-dot mapping, TEM, TGA/DSC, FTIR and N2 adsorption-desorption measurements. Moreover, some analyses were performed on the catalyst after assessment its catalytic activity in the microwave-assisted transesterification reaction. Treated and untreated nanocatalyst presented Ca12Al14O33 structure as support which was covered by carbon groups. The plasma treating was significantly effect on the potassium component as surface active phase and interaction of potassium and calcium with aluminium cations such that no agglomeration of active phases with the highest crystallinity was observed. The plasma treated sample showed better textural properties than untreated nanocatalyst. The main advantage of plasma was clearly observed on the stability of the nanocatalyst that the reduction the activity of untreated sample was more than two times of those for treated nanocatalyst. The plasma treated KOH/Ca12Al14O33-C exhibited no deformation of support structure and leaching of calcium component in the reaction medium against of untreated sample. Therefore, the plasma–microwave hybrid synthesis method provides an excellent rout for preparation of surface modified nanocatalysts for biodiesel production with the highest activity and stability to decrease the production cost.

Spatial Effects of Lateral Deformations of Supporting Structure of Deep Excavation

Spatial Effects of Lateral Deformations of Supporting Structure of Deep Excavation

A New Criterion for Stability Analysis of Tunnel Surrounding Rock-Support Structure Based on the Convergence-Confinement Method

In the decision making of tunnel excavation and support scheme, stability analysis of surrounding rock-support structure is an essential link. Especially in fractured weak zone under complex geological condition, accurately measuring the deformation of support structure has an important significance for fast and safe construction. Based on the application of convergence confinement principle in judging tunnel deformation, this paper presented a new idea of using the ultimate displacement of tunnel initial support to analyze the stability of tunnel surrounding rock-support structure. Then, with a full investigation on the deformation and failure characteristics of highway tunnel surrounding rock at fractured weak zone, the ultimate displacement was got by using methods of numerical calculation and site monitoring measurement. Finally, the stability analysis of support structure in Zhongxing Tunnel was done. It can be arrived that there is a certain gap between true value u and measured value um of surrounding rock deformation. If the measuring points are installed after three excavation cycle, u is approximately equal to 1.6 um. then, based on the analysis of numerical simulation results and monitoring data of Zhongxing Tunnel, the paper indicated that the top and spring of arch are risk regions, reserved deformation of fractured weak zone is not enough, it should be adjusted from 10cm to 20cm.

Study on the Deformation of Supporting Structure for Foundation Pit in Strata with Rock-Soil Combination

Study on the Deformation of Supporting Structure for Foundation Pit in Strata with Rock-Soil Combination

Study on the Deformation of Supporting Structure for Foundation Pit in Strata with Rock-Soil Combination

Taking the deformation of row pile supporting structure of foundation pit in strata with rock-soil combination as the research target and taking an open cut metro deep foundation pit as an example, by in-site monitoring and numerical simulation, analyze the horizontal displacement of retaining piles and the change law of steel support axial force in the strata with rock-soil combination, and summarize the change law of row pile supporting structure in the process of excavation under the conditions of this strata, so that to provide experience and guidance for similar engineering design and construction. The results show that: the structure of foundation pit has obvious effects on deformation and internal force of supporting structure, the result obtained from numerical simulation fits well with the tendency of monitoring data changing. In which, the deformation of row pile supporting structure in the middle and upper part of soil strata is larger, the deformation of middle and lower part of soil strata is comparatively smaller, the lateral deformation of row piles to basement has a tendency of gradual decreasing by taking the interface of rock-soil as a boundary.

Study on Simulation and Stability Analysis of Subway Station Excavation from the Vertical Construction Well

Beijing subway Huangzhuang stations is cross-transfer station. It has a complex tunneling structure. The characteristics of the reverse construction vertical well was been thinking in the course of excavation design. The vertical well excavation and support method, horizontal wells channel excavation and support methods, the main station pilot tunnel excavation and support methods were researched to determine in detail. In order to analysis and evaluation the feasibility of excavation and getting into hole, FLAC3D numerical simulation analysis method was applied to do simulation of the vertical well, horizontal channel and the main cavern excavation. All detail construction course of these three-part were been studied. Excavation and supporting method and progress were all included. The ground surface subsidence, deformation of support structure and strengthen structure were been got. On the condition of the vertical well support structure destruction caused by the horizontal guide hole excavation and the group cave effect caused by guiding cave excavation in main station underground building, the support structure and ground soil stability were studied. The research result gave the base technical support for the project optimization design and construction security.