Deformation Trend Research Articles

Active and passive safety enhancement for batteries from force perspective

Thermal runaway (TR) has become a critical issue for Li-ion battery applications in electric vehicles and energy storage stations. To address this issue, early warning and thermal runaway propagation (TRP) mitigation are significant for the active and passive safety of the battery system, respectively. This study proposes the expansion force as a reliable warning signal, which is proven to provide more interval (>500 s) for escape and rescue compared with voltage and temperature signals. Besides, the TR expansion force changing mechanism due to thermal expansion, gas generation/accumulation, and venting is investigated. Furthermore, the TRP expansion force and deformation changing mechanism is explained from the perspective of expansion, squeeze, and venting. The TRP debris deformation trend is verified through mechanical modeling. The maximum TR expansion force increment (ΔFmax)-capacity (Q) equalization and ΔFmax-cell index equations are proposed based on the TR/TRP tests of three types of prismatic batteries. Moreover, a TRP mitigation structure is proposed to amplify the TR expansion force, which is validated to effectively amplify the force, causing the mechanical destruction of the in-line module holder. A TRP mitigation test proves that the first TR cell capsizes the module holder to hinder the heat transfer between the front/back surfaces of the prismatic batteries when the TR expansion force exceeds the preload. Without enough heat transfer, the TR of the following battery cells cannot be triggered even under jet fire impact. This study guides the active and passive safety design for the prismatic battery system.

Soil and Rockfill Dams Safety Assessment for Henan Province: Monitoring, Analysis and Prediction

It is of great significance to explore the spatial and temporal evolution of soil and rockfill dam deformation, ensuring the safety of people’s lives and healthy economic development. The spatial and temporal evolution patterns of deformation of 17 large soil and rockfill dams in Henan Province were analyzed by using the PS-InSAR technique and 55 Sentinel-1A images from March 2017 to September 2021. Based on factors such as reservoir water level and rainfall, a series of analyses were conducted on the Xiaolangdi soil and rockfill dam, which has the highest dam height and the most prominent deformation problem. The monitoring results show that all the soil and rockfill dams in Henan Province have different degrees of deformation, and there is a close relationship between dam height and deformation. In addition, the deformation rate of the Xiaolangdi soil and rockfill dam in the past five years presents a “Stepped Shape” deformation trend from the top to the bottom of the dam. The deformation of the upper, middle, and lower parts of the dam body reaches 80 mm, 40 mm, and 20 mm, respectively, among which the middle part of the dam crest has the largest deformation. Furthermore, the time series prediction model for sparrow search algorithm Long Short-Term Memory considering the moving average filter (MAF-SSA-LSTM) is proposed to predict and accurately analyze the future deformation of Xiaolangdi soil and rockfill dam with RMSE of 1.526 mm, MAE of 1.447 mm, and MAPE of 2.22%, which proved that the model has high prediction accuracy. It can truly reflect the overall deformation trend of the dam body. The results provide a theoretical basis and decision basis for the census of reservoir safety conditions and deformation history retrieval in Henan Province.

Experimental study on frost heave characteristics and micro-mechanism of fine-grained soil in seasonally frozen regions

In this study, a combination of soil column frost heave tests and microscopic tests (scanning electron microscopy and mercury intrusion test) was conducted to explore the frost heave characteristics of subgrade fine-grained fillings in seasonally frozen regions with different initial water contents under different temperature gradients. Particle image velocimetry (PIV) was employed to clarify the trend in the local deformation at different locations in the soil samples. The test results showed that the total deformation of the soil decreased with the increase in the temperature gradient, and the amount of water replenishment also exhibited a similar trend. Deformation measurements from PIV were in good agreement with the displacement meter measurements. The microscopic test results showed that the porosity of the soil evidently increased after the soil was frozen. Furthermore, when the temperature gradient of the samples was the same, the pore volume of the frozen soil was positively correlated with the initial water content and negatively correlated with the temperature gradient. The study results can help reveal the microscopic mechanism behind the macroscopic frost heave process.

How Camera-to-Subject Distance and Height Affect Breast Measurement and Follow-Up Assessment in Plastic Surgery.

Due to several factors that affect photograph quality, bias is inevitably present in two-dimensional (2D) breast photography. The principal variables affecting image performance at a fixed focus length are the distance between the camera and the subjects and the photography angles. This study aimed to investigate the effects of camera-to-subject distances and camera height on breast measurement parameters to understand the trend of breast deformation and provide guidance for the accurate evaluation of planar follow-up. We enlisted 16 volunteers with various breast cup sizes (A-D). Frontal and lateral photos were obtained with a steady focus of 50 mm at distances between 1.10 m and 2.20 m and at heights between 30 cm above the nipple and 30 cm below the nipple at intervals of 10 cm. Two researchers independently evaluated each volunteer's breast aesthetic parameters, including 11 linear parameters, 3 area parameters, and 3 ratio parameters, using Vernier calipers and Photoshop. The correlation coefficient of the two investigators ranged from 0.922 to 0.999. The results measured by Photoshop were 29.67 ± 5.23% greater than those of the Vernier caliper (p < 0.01). In contrast to ratio parameters, which showed no significant changes in each distance group (p = 1.00), linear parameters and area parameters significantly increased as object distance decreased (p < 0.05). The lower pole of the breast grew wider and flatter and occupied a larger proportion of the breast as height declined. Camera-to-subject distances of 1.5-1.7 m are recommended for stabilized and uniform breast photography. Varying shooting height affects breast distortion. Quantifying the relationship between photographic conditions and breast morphology enables plastic surgeons to conduct more comprehensive and accurate assessments. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266. Bullet point list: 1. The breast morphology will get more distortion with a smaller camera-to-subject distance. 2. Camera-to-subject distances of 1.5~1.7m are recommended for stabilized and uniform breast photography. 3. Height rather than distance affects the breast proportion.

Numerical Simulations and Experimental Verification of T-Structure Welding Deformation Using the Step-by-Step Loading Inherent Strain Method

The existing inherent strain method is improved in this paper to address the shortcomings of the existing inherent strain method in the process of loading inherent strain. Unlike the traditional inherent strain method, which uses one-step loading inherent strain for each weld seam for one-time elastic calculation, the improved inherent strain method uses step-by-step loading inherent strain for each weld seam for multiple elastic calculations to predict welding deformation. The step-by-step loading inherent strain method (SBS-ISM) is more in line with the actual welding deformation generation process. Firstly, the local finite element model of the T-joint was used to analyze the welding deformation and extract the inherent strain by using the thermal elastic–plastic finite element method (TEP-FEM). Subsequently, the one-step loading inherent strain method (OS-ISM) and the step-by-step loading inherent strain method (SBS-ISM) were used to predict the welding deformation for the same local finite element model, respectively. The comparative results showed that the trend and magnitude of welding deformation calculated using SBS-ISM was much closer to those calculated using TEP-FEM. The OS-ISM and SBS-ISM were used to predict the welding deformation of the backward centrifugal fan impeller under different welding sequences, respectively. By comparing the welding deformation results calculated using the two inherent strain methods with the experimental results, it was demonstrated that the step-by-step loading inherent strain method (SBS-ISM) provides more accurate and reliable predictions of welding deformation for large and complex thin-walled T-shaped structural components compared to the one-step loading inherent strain method (OS-ISM).

Experimental and Numerical Investigation of the Buckling Behavior and Strength of Combined Opening Plate Girders in Passenger Ships

High-stiffener-web combined opening girders used on passenger ships are prone to plastic hinge failures around the opening area and overall instability under combined and vertical loads, exhibiting complex buckling behaviors. In response to such situations, a series of numerical simulations and experiments on combined opening girders were conducted, considering several affecting factors such as opening shapes, initial crack defects, strengthening measures and stiffener web dimensions. On the basis of the verification of the reliability of the numerical method, the load-bearing characteristics of the combined open plate girders were investigated. It is concluded that the lumbar round opening can lead to localized plastic hinge failure phenomena, complicating the buckling behavior. In contrast, the inclusion of stiffeners can significantly improve the load-bearing capacity after the point at which instability occurs in the original specimen. In addition, detailed relationships between deformation trends and external loads are illustrated, which can be used as a reference for the optimal design of combined opening plate girders in actual ship structures.

Nonlinear bending–twisting coupling in electromechanical finite deformation of fiber-reinforced tubular dielectric elastomer for soft actuators

Previous studies have revealed that fiber-reinforced tubular dielectric elastomer actuators (TDEAs) exhibit unique characteristics, such as coupled deformation. Therefore, the present study focuses on the electromechanical behavior of fiber-reinforced TDEAs and analyzes induced coupled bending–twisting deformation analytically and numerically. An analytical framework is derived from the Helmholtz free energy of the system and, using the variation method, leads to equilibrium equations. Despite the limitation of homogeneous deformation, the results indicate relevant facts about the electromechanical behavior and stability of the considered TDEA. On the other hand, a numerical method is devised based on the nonlinear continuum, electro-elasticity, and large deformation theory. The resultant model and presented tangent modulus are validated using experimental data. The model makes it possible to develop a FEM algorithm and explore the behavior of the TDEA under various loading and boundary conditions. For example, the current paper presents the final deformation of a fiber-reinforced TDEA under internal pressure, axial force, and torque. It also explores the bending deformation of a designed tubular bending actuator using numerical analysis and the developed model. Analytical and numerical results share similar trends in longitudinal, radial, and torsional deformations before instability. It is also evident that for voltages higher than the critical voltage, when instability is detected, fiber orientation may cause more significant effects. Analytical and numerical findings confirm coupled deformations in different directions.

The Viscoplastic Behavior of Natural Hydrate‐Bearing Sandy‐Silts Under Uniaxial Strain Compression (K0 Loading)

AbstractThe in‐situ stress state and geomechanical properties of hydrate‐bearing sediments impact hydrate formation and gas production strategies. We explore the uniaxial strain compression and stress evolution of natural hydrate‐bearing sandy‐silts from Green Canyon Block 955 in the deep‐water Gulf of Mexico. We performed constant rate of strain uniaxial strain experiments, interrupted by periods where we held the axial stress constant, to explore the vertical deformation and the evolution of the ratio of lateral to axial effective stress (K0) with time. The hydrate‐bearing sandy‐silt is stiffer and has a larger K0 than the equivalent hydrate‐free sediment upon loading. During stress holds, the void ratio decreases sigmoidally with the log of time, and K0 converges to isotropic conditions. We interpret that during loading, the hydrate bears the load and deforms. With time, the hydrate redistributes the load and K0 increases. We used a viscoelastic model to describe the behavior. The model accurately captures deformation and K0 trends but does not reproduce all the complex interactions of the hydrate with the porous skeleton. We anticipate that viscous effects within hydrate sediments will impact reservoir compression and stresses during production (hours to days), result in isotropic stress state over geological timescales, and explain the creeping movement in submarine landslides.

A Multi-Source Intelligent Fusion Assessment Method for Dynamic Construction Risk of Subway Deep Foundation Pit: A Case Study

The construction of a subway deep foundation pit is complex and risky, thus multiple safety risk factors bring great challenges to evaluating the safety status accurately. Advanced monitoring technology equipment could obtain a large number of monitoring data, and how integrating complex and diversified monitoring data to assess the safety risk of foundation pits has become a new problem. Therefore, an intelligent multi-source fusion assessment model is proposed. This model is mainly used for solving risk probability distribution, deep learning, and intelligent prediction of monitoring indicators, and then evaluating safety status by fusing various parameters of multiple indicators. Thus, based on the data of deep learning and the measured multivariate data, the dynamic risk during foundation pit construction can be obtained. Moreover, a typical case study was performed through monitoring and carrying out the risk assessment which is located at the Martyrs’ Lingyuan Station of Jinnan Metro Line R2, China. In this case, the PSO-SVM and LSTM models are used to predict the deformation trend, and the monitoring data is reliable with high precision. After multi-index fusion model calculation, the results show that the foundation pit structure is in a safe state, and the evaluation situation is basically consistent with the site. Consequently, the prediction of the new multi-source intelligent fusion risk assessment method is convincing.

InSAR-based method for monitoring the long-time evolutions and spatial-temporal distributions of unstable slopes with the impact of water-level fluctuation: A case study in the Xiluodu reservoir

Slope instability in reservoir areas is one of the greatest concerns for public and governments worldwide. The long-time evolution of the unstable slopes in reservoir areas after the impoundments remain poorly understood. Among the technologies applied to detecting and monitoring unstable slopes, interferometry synthetic aperture radar (InSAR) technology is one of the most effective. However, owing to the slopes in a reservoir suffering from periodic water-level fluctuations, InSAR technology has shortcomings for monitoring unstable slopes with large displacement for a long time. In this study, a post-processing method of InSAR and a practical strategy were proposed to monitor the long-time evolution of the unstable slopes in reservoir areas both spatially and temporally. The strategy can capture the evolution trends of the unstable slopes based on the variations in their deformation areas with reservoir water-level fluctuations for a long time. The case study was carried out in the Xiluodu reservoir area of China. The monitoring data of the unstable slopes before and after reservoir impoundment were extracted from multi-source SAR data, including those from ALOS-1, ENVISAT ASAR, and Sentinel-1. It was found that there were 40 unstable slopes before the reservoir impoundment and 152 unstable slopes after the reservoir impoundment. Of the 152 slopes, 142 slopes (94%) began deforming in the first 3 years after reservoir impoundment, 15 slopes have been experiencing continuous deformation, and 137 slopes underwent intermittent deformation. The areas of 79 slopes (52%) increased during the water-level drawdown periods and decreased during the rising periods. The areas of 22 slopes (14%) demonstrated the opposite trend, and the areas of 51 slopes (34%) increased independently of the water-level fluctuations. In terms of evolution trends in the deformation area, 30% of slopes experienced a decreasing trend, 15% were under a constant deformation trend, and 55% showed an increasing trend. The distribution of the unstable slopes varied from the dam site to the end of the reservoir, and most of them favorited the areas where slope angle and height were 20–35° and 30–300 m, respectively. The soil slopes composed of the previous landslide deposits were prone to deformation, followed by the dip to overdip layered rock slopes.

Modelling of hygro-mechanical behaviour of wooden panel paintings: model calibration and artworks characterisation

Wooden Panel Paintings (WPP) are among the most significant historical and artistic artifacts from the Middle Ages and Renaissance and pose a challenge to conservators and scientists in both their comprehension and conservation. From a structural point of view, they can be considered as multi-layered objects, consisting of a wooden support and several pictorial layers. The wooden support, hygroscopic in nature, constantly seeks equilibrium with the humidity of the environment, and consequently deforms. Based on a series of hygroscopic tests carried out on six original WPPs, the present work aims to model their deformation tendencies induced by moisture changes and to characterise them by means of an inverse identification process. The sensitivity analysis of this study provided valuable insights into the complexity of the phenomenon of WPP deformation: even small variations in input variables (board anatomy, stiffness and emissivity of pictorial layers) led to significant changes in the deformation trend over time, highlighting the high variability of the physical problem under investigation. Sobol's analysis variance confirmed this complexity, demonstrating the different levels of influence of input variables and the existence of interactions between them. Overall, the results of this analysis highlighted the need to carefully evaluate the interactions and uncertainties in input variables to fully understand the complexity of the system. The iterative optimization process led to numerical results tending to agree with experimental data, with most results showing a very high correlation. This suggests that the chosen variables and modelling assumptions sufficiently described the physical system and that numerical models can be accurately calibrated. The proposed concept of 'learning from objects', by conducting experimental investigations specifically dedicated to understanding the deformation tendencies of the artwork, is essential. In this approach, numerical analysis is used in conjunction with experiments to gain a deeper understanding of the artwork, characterise it and extract valuable information.

Comparison of ARIMA and LSTM in Predicting Structural Deformation of Tunnels during Operation Period

Accurately predicting the structural deformation trend of tunnels during operation is significant to improve the scientificity of tunnel safety maintenance. With the development of data science, structural deformation prediction methods based on time-series data have attracted attention. Auto Regressive Integrated Moving Average model (ARIMA) is a classical statistical analysis model, which is suitable for processing non-stationary time-series data. Long- and Short-Term Memory (LSTM) is a special cyclic neural network that can learn long-term dependent information in time series. Both are widely used in the field of temporal prediction. In view of the lack of time-series prediction in the tunnel deformation field, the body of this paper uses historical data of the Xinjian Road and the Dalian Road tunnel in Shanghai to propose a new way of modeling based on single points and road sections. ARIMA and LSTM models are applied in comprehensive experiments, and the results show that: (1) Both LSTM and ARIMA models have great performance for settlement and convergence deformation. (2) The overall robustness of ARIMA is better than that of LSTM, and it is more adaptable to the datasets. (3) The model prediction performance is closely related to the data quality. ARIMA has more stable performance under the lack of data volume, while LSTM has better performance with high-quality data and higher upper limit.

Bayesian optimization and ensemble learning algorithm combined method for deformation prediction of concrete dam

Concrete dams, as a significant infrastructure project, necessitate a prioritization of operational safety. Deformation is an essential element in the safety monitoring of concrete dams. The development of monitoring models aimed at predicting the trend of dam deformation is the fundamental tool for ensuring dam safety. The accuracy of the monitoring model is paramount in guaranteeing the reliability of subsequent safety assessments. Consequently, this paper proposes a novel combined prediction model for concrete dams, based on Bayesian Optimization (BO) and Random Forests (RF), to achieve high-precision prediction of deformation. Initially, the monitoring data were pre-processed, and the input parameters for the RF model were established. Subsequently, BO based on Gaussian processes optimizes various hyperparameters of the RF models and determines the optimal parameters. Finally, based on the Gini coefficient in this study, the significance of the output characteristic explained the relationship between the dam deformation and its influencing factors. Example analysis and model validation results evinced that the proposed model's prediction accuracy, in the test set, is superior to that of other benchmark models, and the residuals' dispersion is negligible. The proposed combined model has significant engineering implications and provides a novel method for concrete dam safety monitoring.

Deformation Control of the Existing Medium-Low-Speed Maglev Metro Viaduct over a Double-Line Bored Tunnel

Taking a double-line underground excavation subway tunnel underneath the medium-low-speed Maglev bridge section of the Beijing S1 Metro line as a project reference, the deformation control index of the Maglev metro bridge and track panel was studied using numerical simulation and data monitoring, under the conditions of deep-hole grouting measures for the soil layer around the excavation tunnel and active lifting for the superstructure of the viaduct. The results of the numerical simulation show that the maximum deformation value of the pier is −1.73 mm and the maximum vertical deformation value of the Maglev rail track is −1.56 mm. Monitoring shows that the maximum vertical deformation value of the magnetic levitation rail is −1.25 mm and the deformation is within the allowable range. Both numerical simulation and field monitoring results reflect the deformation trend of existing structures; the deep-hole grouting measures taken to strengthen the soil layer around the tunnel and the upper structure of the active roof elevation frame can effectively control the deformation of the existing structure. The study can provide guidance and reference for similar projects.

Time-Series InSAR Deformation Monitoring of High Fill Characteristic Canal of South–North Water Diversion Project in China

The Middle Route of the South–North Water Diversion Project has changed the water resources pattern in China. As advanced equipment for the country, it is responsible for the water supply “lifeline” of Beijing, Tianjin, Hebei, Henan, etc. Ensuring its safe operation is a top priority to promote social stability and coordinated economic development between the North and the South. Used persistent scatterer interferometric synthetic aperture radar (PS-InSAR) technology to monitor the deformation of the high fill characteristic canal in Wenzhuang Village, Ye County, during the period from October 2016 to June 2017 for the South–North Water Diversion Project showed that there was significant deformation on the 1 km-long slope of the east bank of the canal, with the maximum deformation volume reaching 36 mm. Through the comparison and verification with the second order leveling data, there are more than 87% of the root mean square error of both less than ±2 mm. The correlation coefficient is 0.96, and the two were highly consistent in deformation trends and values. Through the vertical and cross-sectional analysis of the canal’s east bank and four key monitoring sections, it was found that the east bank of the canal presents overall uneven subsidence, and the closer the canal is to the water, the greater the canal deformation, and vice versa. Further comparison of the PS-InSAR deformation results of the canal from October 2016 to February 2018 proves that this technology cannot only monitor the subsidence range and rate of the South–North Water Diversion canal but also accurately identify the subsidence sequence of the east and west banks. It can provide reliable technical support for the safety monitoring and disaster prevention of the South–North Water Diversion canal characterized by high fill and deep excavation.

A METHOD FOR MEASURING LARGE-SCALE DEFORMATION OF LANDSLIDE BODIES BASED ON NAP-OF-THE-OBJECT PHOTOGRAMMETRY

Abstract. Geological disasters such as landslides and debris flows pose a serious threat to human life and property. To mitigate this risk, monitoring and early warning systems are essential. However, monitoring high-angle landslide areas can be challenging due to the steep and complex terrain, making it difficult to carry out large-scale and refined deformation measurements using existing methods. This paper proposes a method to measure the large-scale deformation of landslide bodies based on nap-of-the-object photogrammetry. The method uses UAVs to acquire high-resolution 3D models of steep and high landslide areas at multiple time periods. Then, 3D model matching is employed to obtain accurate variation information for terrain deformation measurement. To obtain fine 3D models, a terrain-adaptive nap-of-the-object photogrammetric flight planning is applied to design the optimal photographic positions and directions for capturing ultra-high-resolution images. The images are processed using photogrammetric principles and technologies to produce fine 3D models. For terrain deformation measurement, an algorithm is proposed to obtain 3D correspondences by fusing DEM differential and 3D model texture matching. The 3D points variation vectors are then calculated, and the large-scale deformation measurement results of the landslide body can be derived after the vectors are aggregated. Experiments were conducted on the Lijiebeishan landslide in Gansu Province, western China. The results showed that the proposed deformation measurement method was highly effective in accurately detecting areas with displacement greater than 5 cm, and the large-scale deformation trend is consistent with GNSS predictions. In conclusion, the proposed method is an effective way to measure the large-scale deformation of landslide bodies in high-angle landslide areas, providing a valuable tool for monitoring and early warning systems.

Research on large deformation control technology of highly weathered carbonaceous slate tunnel

Abstract In order to further explore the large deformation control technology of high ground stress soft rock tunnel, this study takes the highly weathered carbonaceous shale section of Muzhailing tunnel as the research background, the large deformation control effect of scheme 1 “three-step method” and scheme 2 “pilot tunnel expansion method” are compared and analysed by field test and numerical simulation. The results show that the numerical simulation results are consistent with the field test, and the deformation trend of the tunnel is the same. The maximum deformation of the tunnel occurs at the middle step. From the perspective of tunnel deformation, control effect is reduced by about 10% compared with scheme 1, and the deformation of both schemes does not exceed the reserved deformation (400 mm). From the perspective of construction efficiency, the construction efficiency of scheme 2 is 23.07% lower than that of scheme 1. Taking into account the deformation control effect and construction efficiency, it is recommended that the three-step method should be adopted in the construction of this section, and the research results can provide a reference for the construction of the carbonaceous slate section of the tunnel.

Experimental and Analytical Evaluations of Ground Behaviors on Changing in Groundwater Level in Bangkok, Thailand

Groundwater level changes have numerous effects on buildings, such as differential ground deformation and cracking on the wall. In Bangkok, Thailand, change in groundwater levels changing was caused by groundwater pumping that took place from 1978 to 1997. This is the main effect of ground deformation in a wide area of the Bangkok plain. According to the regulation of groundwater pumping in Bangkok and urban areas, the trend of groundwater level tended to recover around the year 1997. However, the ground settlement still occurs for a while after groundwater recovery. The objective of this study is to evaluate and compare the capability of each approach for the ground deformation and the pile capacity in the situation of groundwater level change. Data in this study were obtained from the previous centrifuge test which had been modeled for the Bangkok area. The ground behavior and pile load capacity behavior were verified using numerical modeling. Both experimental modeling and numerical modeling represent very similar trends of ground deformation. The pile capacity results from both models’ increase while the groundwater level decreases and the pile capacity decreases when groundwater is recovered. The numerical modeling results reveal an overestimate of the ground behavior. However, both results present the loss of pile capacity in the range of 8 to 25% of maximum load when the groundwater level reach to the minimum level.

Lubrication characteristics and thermal deformation of hydrostatic thrust bearing based on conjugate heat transfer

PurposeThe purpose of this paper is to analyze the variation of temperature field, pressure field and deformation of hydrostatic thrust bearing under different working conditions, so as to provide a theoretical basis for improving accuracy and reliability.Design/methodology/approachIn this study, the double rectangular hydrostatic bearing of type Q1-224 was selected as the research object, and the simulation was carried out according to different working conditions, and the obtained data were summarized regularly.FindingsIt is found that the overall temperature of hydrostatic bearing increases with the increase of speed and load, and the increase in load will result in a larger pressure distribution which first increases and then decreases with the speed. The deformation trend of the deformation field is found, and it is found that the force deformation is larger than the thermal deformation at low rotational speed, and the thermal deformation is larger than the force deformation at high rotational speed.Originality/valueIn this study, the fluid-structure coupling method of conjugate heat transfer is applied to study the whole hydrostatic bearing. Most of the previous studies only studied the oil film and considered the influence of the convective heat transfer between the hydrostatic bearing and the air in heat transfer, which is rarely seen in the previous research literature.

Research on the Control of Excavation Deformation of Super Deep Foundation Pit Adjacent to the Existing Old Masonry Structure Building

In order to ensure the safety and stability of the existing old masonry structure houses in the process of dewatering and excavation of the super deep foundation pit of the subway, the support form of a water stop curtain combined with bored cast-in-place piles and internal support is adopted, and the rotary jet grouting piles are constructed around the houses, and sleeve valve pipes are embedded, and the soil and house foundation are grouted and strengthened. The deformation of the building foundation is analyzed by the finite element method. The results show that the deformation of adjacent buildings is mainly uniform at the initial stage of foundation pit dewatering and excavation. With the increase of foundation pit dewatering and excavation depth, the deformation of adjacent buildings shows significant differential characteristics, and the maximum displacement of buildings is settlement deformation. The field monitoring data show that the actual deformation trend and value range of the building structure are basically consistent with the finite element calculation results, and no new damage is found in the building structure during the construction process. Effective foundation pit support method and soil layer reinforcement method can effectively reduce the impact of foundation pit on the deformation of adjacent buildings.