scholarly journals Stability Evaluation Method of Hole Wall for Bored Pile under Blasting Impact

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 79
Author(s):  
Qiuwei Yang ◽  
Zhikun Ba ◽  
Zhuo Zhao ◽  
Xi Peng ◽  
Yun Sun
Keyword(s):  
Pile Foundation ◽  
Evaluation Method ◽  
Impact Load ◽  
Stability Evaluation ◽  
Foundation Construction ◽  
Concentration Problem ◽  
Hole Wall ◽  
Failure Theory ◽  
Collapse Failure ◽  
The Stability

Blasting impact load may be encountered during the construction of some pile foundation projects. Due to the effect of blasting impact, hole collapse can easily occur in the hole-forming stage of pile foundation construction. In order to prevent hole collapse, it is very necessary to evaluate the stability of a pile hole wall before pile foundation construction. The calculation of hole collapse can usually be attributed to an axisymmetric circular hole stress concentration problem. However, the existing collapse failure theory of pile hole hardly considers the effect of blasting impact load. In view of this, this paper proposes the stability evaluation method of a pile hole wall under blasting impact. Compared with the existing collapse failure theory, the proposed method fully considers the effect of blasting impact stress. Using Mohr–Coulomb strength theory and symmetry analysis, the strength condition of collapse failure is established in this work for accurate evaluation of the stability of a hole wall. The proposed stability evaluation method is demonstrated by a pile foundation construction project of a bridge. Moreover, a shaking table test on the pile hole model was performed to verify the proposed method by experimental data. The results indicate the effectiveness and usability of the proposed method. The proposed method provides a feasible way for the stability analysis of a pile hole wall under blasting impact.

scholarly journals Study on Dynamic Behavior of Bridge Pier by Impact Load Test Considering Scour

2020 ◽  
Vol 10 (19) ◽  
pp. 6741
Author(s):  
Myungjae Lee ◽  
Mintaek Yoo ◽  
Hyun-Seok Jung ◽  
Ki Hyun Kim ◽  
Il-Wha Lee
Keyword(s):  
Natural Frequency ◽  
Evaluation Method ◽  
Impact Load ◽  
Full Scale ◽  
Load Test ◽  
Scale Model ◽  
Second Mode ◽  
Surcharge Load ◽  
The Stability ◽  
The Impact

In this study, for the establishment of a safety evaluation method, non-destructive tests were performed by developing a full-scale model pier and simulating scour on the ground adjacent to a field pier. The surcharge load (0–250 kN) was applied to the full-scale model pier to analyze the load’s effect on the stability. For analyzing the pier’s behavior according to the impact direction, an impact was applied in the bridge axis direction, pier length direction, and pier’s outside direction. The impact height corresponded to the top of the pier. A 1-m deep scour was simulated along one side of the ground, which was adjacent to the pier foundation. The acceleration was measured using accelerometers when an impact was applied. The natural frequency, according to the impact direction and surcharge load, was calculated using a fast Fourier transform (FFT). In addition, the first mode (vibratory), second mode (vibratory), and third modes (torsion) were analyzed according to the pier behavior using the phase difference, and the effect of the scour occurrence on the natural frequency was analyzed. The first mode was most affected by the surcharge load and scour. The stability of the pier can be determined using the second mode, and the direction of the scour can be determined using the third mode.

scholarly journals A Method for Quantitative Evaluation of Seismic Stability of Loess Slope Based on the Shaking Table Model Test

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pu Xiaowu ◽  
Wang Lanmin ◽  
Wang Ping ◽  
Chai Shaofeng ◽  
Xu Shiyang
Keyword(s):  
Model Test ◽  
Evaluation Method ◽  
Shaking Table ◽  
Seismic Stability ◽  
Stability Evaluation ◽  
Loess Slope ◽  
Critical Instability ◽  
Table Model ◽  
The Stability ◽  
Shaking Table Model Test

The large-scale shaking table model test, which can directly reproduce the process of slope instability and failure, is an important technical means for the prediction and evaluation of slope seismic stability. However, up to now, the systematic slope stability evaluation method based on the shaking table slope model test has not been established, which limits the application of the expensive shaking table model test in slope seismic design. Therefore, the slope stability evaluation method based on the model test needs to be developed and innovated. In this research, through three loess slope model tests with different rainfall, according to the change law of the peak value of transfer function spectrum, combined with the macrodestructive characteristics of the slope model, an accurate calculation method of the critical instability acceleration of the slope is proposed. Based on the behavior similarity theory, for the shaking table model test of slope whose soil cohesion cannot meet the similarity ratio, the reduction method of applying the critical instability acceleration obtained from the model test to prototype slope is proposed. Based on first-order natural frequency and damping ratio extracted from the TF spectrum curve, a calculation method for the stability factor Fs of loess slope based on the shaking table model test is proposed, and the stability factors of loess slope under the action of different seismic ground motion would be quantitatively calculated. The above methods provide another effective way for qualitative prediction and evaluation of seismic stability of loess slope.

scholarly journals Evaluation of Slope Stability of Reservoir Considering Heterogeneous Soil Properties

2020 ◽  
Vol 20 (6) ◽  
pp. 167-175
Author(s):  
Seungwon Shin ◽  
Sangbeen Lee ◽  
Sungsu Lee ◽  
Jongwon Jung
Keyword(s):  
Slope Stability ◽  
Spatial Heterogeneity ◽  
Material Properties ◽  
Evaluation Method ◽  
Stability Evaluation ◽  
Heterogeneous Soil ◽  
Local Properties ◽  
The Stability ◽  
The Cost ◽  
Cost Effect

The slope stability evaluation of reservoirs is required because of the aging of reservoirs. Reservoir levees are designed to achieve homogeneous construction, but the spatial heterogeneity of the material properties of reservoirs is unavoidable. Because the existing method for evaluating reservoir stability is limited in terms of considering the spatial heterogeneity of material properties, the stability evaluation was conducted in this study, in which the spatial heterogeneity and uncertainty of the material properties of the reservoir levee were considered. In addition, the results for the existing and proposed methods were compared and analyzed, and the variability of the entire material properties of the reservoir levee, instead of spatial heterogeneity, was reflected. The evaluation results confirmed that the probability of failure obtained using the proposed method was lower than that for the existing stability evaluation method, considering the variations in material properties because the levee did not reach the critical state, owing to changes in local properties. Therefore, the proposed method is useful for the cost-effect repair and reinforcement of reservoir slopes, compared to the existing slope stability evaluation method.

scholarly journals Evaluation of Reservoir Slope Stability Considering Friction Angle Uncertainty and Earthquakes

2020 ◽  
Vol 20 (5) ◽  
pp. 273-280
Author(s):  
Seungwon Shin ◽  
Seongnoh Ahn ◽  
Sungsu Lee ◽  
Jongwon Jung
Keyword(s):  
Water Level ◽  
Evaluation Method ◽  
Limit Equilibrium ◽  
Weather Conditions ◽  
Friction Angle ◽  
Soil Strength ◽  
Seismic Events ◽  
Stability Evaluation ◽  
Strength Parameters ◽  
The Stability

Approximately 76% of the reservoirs built in Korea are facilities that are more than 50 years old. The risk of disasters has increased because of reservoir aging and the deepening polarization of drought and floods caused by abnormal weather conditions. In addition, the number of earthquakes has been gradually increasing in Korea, and anxiety has increased significantly because of the recent series of large earthquakes since the earthquakes in Pohang and Gyeongju. Accordingly, risk assessment and preparation are required through the stability evaluation of earthquakes in old reservoirs. The stability evaluation method, based on the limit equilibrium method, depends highly on the soil strength parameters; hence, it is essential to identify the soil strength parameters accurately. However, even though the soil strength parameters are of the same layer, they have different values because of the heterogeneity of the ground. It is difficult to select the representative value of the soil strength parameters because of the time and economic constraints of the ground survey. Therefore, in this study, the probability of failure of an old reservoir owing to seismic events was calculated, and the stability was evaluated. The water level and the uncertainty of the strength constant of the reservoir were considered. The analysis showed that the probability of collapse has increased because of the increase in the water level and the coefficient of variation of the friction angle, and the stability of the reservoir, considering the seismic events, was found to not satisfy the minimum factor of safety for slope activities.

scholarly journals On-Site Monitoring for the Stability Evaluation of a Highway Tunnel above Goaves of Multi-Layer Coal Seams

2021 ◽  
Vol 11 (16) ◽  
pp. 7383
Author(s):  
Guangtao Cai ◽  
Wanghua Sui ◽  
Shenglin Wu ◽  
Jilin Wang ◽  
Jiaxing Chen
Keyword(s):  
Coal Seam ◽  
Evaluation Method ◽  
Safety Evaluation ◽  
Shanxi Province ◽  
Stability Evaluation ◽  
Coal Seams ◽  
Highway Tunnel ◽  
Site Monitoring ◽  
The Stability ◽  
The Individual

This paper presents the on-site monitoring of a medium–long highway tunnel constructed above a goaf of a multi-layer coal seam, in order to evaluate and maintain safety during operation. The case study of the Tianzimiao medium–long highway tunnel in Shanxi province was conducted above a goaf of a multi-layer coal seam with typical geological and engineering conditions in China, where a total of four coal seams (seam no. 3, 8, 12, and 15) were mined out with a total thickness of up to 11 m. Methods including data collection, engineering geological survey, drilling, geophysical prospecting, testing, and on-site monitoring were adopted, and a geo-mechanical model was established to conduct the research. Stratified monitoring was applied to investigate the individual settlement and deformation of the four layers of the goaf below, and a prediction of the possible deformation in tunnel floor ground was made based on the stratified measurements. The settlement of the tunnel sidewall, the internal stress in the fractured zone of the surrounding rock, and the deformation above the tunnel entrance were also monitored, and the monitoring data were compared with the numerical simulation results for the safety evaluation of the tunnel. The results show that the current tunnel deformation values and trend are both within the safety scope of the evaluation and prediction. The stability evaluation method for the multi-layer goaf used in this paper and the long-term on-site monitoring and timely feedback during operation is helpful to ensure the safe use of the tunnels above the goaves of multi-layer thick coal seams.

The Stability Evaluation of Radial Ring Rolling

2012 ◽  
Vol 482-484 ◽  
pp. 1229-1232
Author(s):  
Yong Xing Hao ◽  
Ya Mei Han ◽  
Hai Tao Cheng ◽  
Hua Ying Guo
Keyword(s):  
Evaluation Method ◽  
Rolling Process ◽  
Theory And Practice ◽  
Ring Rolling ◽  
Stability Evaluation ◽  
Dynamic Phenomenon ◽  
The Future ◽  
The Stability ◽  
Ring Rolling Process ◽  
Dynamic Research

In the Non-stability radial ring rolling process, the ring may collide with the guide roll, making the ring become a polygon. In extreme cases the rolling process could be terminated and the ring be scrapped. The stability evaluation of radial ring rolling has great theory and practice significance. In this article, based on the kinematics theory, a classified research on the dynamic phenomenon of radial ring rolling was done, and a stability evaluation method during the radial ring rolling was put forward. The evaluation provided a good base for the future ring rolling dynamic research.

The Evaluation of Surrounding Rock Stability around Underground Engineerings Based on Improved Extension Evaluation Method

2012 ◽  
Vol 594-597 ◽  
pp. 339-342
Author(s):  
Suo Juan Zhang ◽  
Guo Qing Qiu ◽  
Wen Bin Xie ◽  
Xiu Li Qi ◽  
Zhi Guang Ao ◽  
...  
Keyword(s):  
Correlation Function ◽  
Evaluation Method ◽  
Surrounding Rock ◽  
Extension Theory ◽  
Stability Evaluation ◽  
Underground Engineering ◽  
Extension Method ◽  
Rock Stability ◽  
The Stability ◽  
Extension Evaluation

Combined with the research of the stability grade of surrounding rock, this paper put forward into the extension method on surrounding rock stability around underground engineerings with extension theory. The extension method was improved the value of the limited field, the correlation function and weights coefficients to establish the stability evaluation method. The method was successfully applied into the underground engineering case, which has provided scientific reference for design and construction of underground engineerings.

scholarly journals Research on the stability evaluation method of anchored slopes based on group decision making and matter element analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Peng Xia ◽  
Chunye Ying
Keyword(s):  
Decision Theory ◽  
Evaluation Method ◽  
Group Decision ◽  
Stability Evaluation ◽  
Analytic Hierarchy ◽  
Entropy Model ◽  
Element Analysis ◽  
Matter Element Analysis ◽  
Correlation Degree ◽  
The Stability

AbstractThis research is focused on the evaluation method of anchored slope stability, and an accurate evaluation method with a simple operation is proposed. Group decision theory and the analytic hierarchy process are used to determine the weight of each evaluation element, the correlation degree of each indicator is determined based on matter element analysis theory, and inverse hierarchical calculations are performed based on the obtained weight value and correlation degree to finally obtain the criteria layer correlation degree used for stability evaluation. The results show the following: (1) the evaluation method better integrates the effects of multiple factors on the stability of the anchored slope, and the evaluation results are accurate and consistent with the actual situation of the project; (2) the evaluation method can make full use of the experience of the expert group and effectively avoid the evaluation error caused by the subjective deviation of a single expert; (3) the group decision theory-entropy model was introduced to realize the quantitative evaluation of the reliability of expert scoring and effectively improve the efficiency of expert discussion; and (4) the evaluation result is intuitive, and the correlation degree obtained can not only reflect the stability grade of the anchored slope but also reflect the "distance" between the anchored slope and other stability grades.

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