Stability Calculation Method Research Articles

A Calculation Method of Overall Stability for Flat Plate Stiffened Panels Under Compression

A Calculation Method of Overall Stability for Flat Plate Stiffened Panels Under Compression

Stress field and stability calculation method for unloading slope considering the influence of terrain

Stress field and stability calculation method for unloading slope considering the influence of terrain

A process-oriented approach for identifying potential landslides considering time-dependent behaviors beyond geomorphological features

Geomorphological features are commonly used to identify potential landslides. Nevertheless, overemphasis on these features could lead to misjudgment. This research proposes a process-oriented approach for potential landslide identification that considers time-dependent behaviors. The method integrates comprehensive remote sensing and geological analysis to qualitatively assess slope stability, and employs numerical analysis to quantitatively calculate aging stability. Specifically, a time-dependent stability calculation method for anticlinal slopes is developed and implemented in discrete element software, incorporating time-dependent mechanical and strength reduction calculations. By considering the time-dependent evolution of slopes, this method highlights the importance of both geomorphological features and time-dependent behaviors in landslide identification. This method has been applied to the Jiarishan slope (JRS) on the Qinghai-Tibet Plateau as a case study. The results show that the JRS, despite having landslide geomorphology, is a stable slope, highlighting the risk of misjudgment when relying solely on geomorphological features. This work provides insights into the geomorphological characterization and evolution history of the JRS and offers valuable guidance for studying slopes with similar landslide geomorphology. Furthermore, the process-oriented method incorporating time-dependent evolution provides a means to evaluate potential landslides, reducing misjudgment due to excessive reliance on geomorphological features.

Comparison of different hydrological and stability assumptions for physically-based modeling of shallow landslides

Physically-based models are reliable techniques for landslide susceptibility assessment, therefore, several models have been proposed in the literature. In this study, two different hydrological models (FSLAM and TRIGRS) and two slope stability calculation methods (infinite slope and limit equilibrium method with spherical failure surface in SCOOPS3D) were compared. The rainfall-triggered shallow landslides that occurred in Kaptanpaşa, Rize (Turkey) in 2017 were selected as a case study. The main focus is investigating the impact of landslide morphology on the success of the slope stability models. For this purpose, landslides in the inventory were grouped according to their morphological characteristics, such as the landslide depth, length, width and their ratios, and their compatibility with model assumptions (e.g. the infinite slope assumption). Then, the model performances in different landslide types were evaluated separately. To calibrate the model parameters a new time-saving, semi-automated calibration strategy, based on a sensitivity analysis, is proposed. Concretely, stability parameters c′∅′Z were calibrated via a MATLAB code by considering the area under the curve (AUC) and extreme conditions: saturated and initial conditions. Overall, SCOOPS3D is deduced to have better performance than infinite slope analysis. However, the accuracy of SCOOPS3D is revealed to decrease for landslides with a high ratio of length/depth and width/depth. From the comparison of hydrological models, FSLAM yielded more plausible results than TRIGRS with the available data. It is demonstrated that the morphological features of the landslides significantly influence the performance of the physically-based stability models. Furthermore, it is highlighted that the resolution of the Digital Elevation Model in comparison to the width and length of the landslides in an inventory can be influential in the performance of the physical model. 10 m resolution of DEM is deemed to be suitable for the study area judging the predictive performance in small landslides.

Study on Calculation Method of Stability of Damaged Sliding Dangerous Rock on Reservoir Bank

The rapid destruction of dangerous rock produces a large amount of energy, causing heavy casualties and economic losses every year. There are various failure modes and stability calculation methods of dangerous rock. The common failure modes of dangerous rock are tipping mode, sliding mode and falling mode. For large tower pillar dangerous rock with degraded foundation, it is unreasonable to use conventional stability calculation methods to calculate the stability of dangerous rock. This paper takes Jianchuandong dangerous rock in Wushan County as the research background, considering the expansion of rock cavity of damaged dangerous rock base and the deterioration of rock mass in the base of large tower column reservoir bank, and establishes the stability calculation method of dangerous rock suitable for the damage deterioration of the base. It is innovative on the basis of the traditional stability calculation method of dangerous rock, which has important practical significance and theoretical basis for the calculation of the stability of unconventional dangerous rock.

Real-time ship stability evaluation program through deterministic method based on second-generation intact stability

IMO suggests Second-Generation Intact Stability Criterion (SGISC), which consists of five failure modes, because of continuous accidents due to a lack of ship stability. In this study, Level 1 and Level 2 stability of SGISC were evaluated for three stability failure modes (Dead Ship Condition, Surf-riding, and Excessive Acceleration). Level 1 was calculated in the same way as the second-generation intact stability calculation method, and Level 2 was calculated in a deterministic manner by using a real-time maritime environment rather than a probabilistic approach for all maritime environments. Based on this, a program was developed to visualize dangerous and safe areas on a map. Using the developed program, it is expected that SGISC can be used not only in the design stage, but also in the operation stage of ships, such as route planning or selection of operating locations in the ocean.

Simplified calculation method and stability analysis of top beam cooperative pile–anchor supporting slope structure

Aiming at the problem of insufficient research on the action mechanism and stability calculation method of the top beam in the pile-anchor support structure, firstly the force and deformation model are established based on the elastic fulcrum method and the deformation coordination principle of the pile-anchor structure at the pile top and the anchor end in this paper. Secondly, the calculation model of the support structure under the synergy of the crown and beam and the simplified calculation method of the internal force, displacement and overall stability of the slope are constructed. Finally, combined with an engineering example, a MATLAB program was compiled for calculation, and the pile-anchor structures with crowned beams and without crowned beams were simulated and calculated by the finite element software PLAXIS 3D and Geo Studio. These three aspects are compared and verified. The results show that the internal force, deformation and minimum safety factor calculated by the method in this paper are basically consistent with the numerical simulation calculation results of the top beam condition; the existence of the top beam effectively enhances the bearing capacity of the pile body, and also restricts the displacement of the pile top development; the synergy of the crown and beam makes the safety factor of the slope increase significantly and improves the safety and stability of the slope. The research in this paper can provide a certain reference value for the theoretical calculation and design of the pile-anchor supported slope considering the top beam in engineering practice.

Study on the slope dynamic stability considering the progressive failure of the slip surface under earthquake

The strength of a rock-soil mass shows complex and obvious weakening characteristics under seismic dynamic load. The previous stability analysis methods of a seismic slope do not fully depict the attenuation law of geotechnical materials and cannot truly reflect the stable state of a slope under earthquake action. Based on the theoretical analysis of the progressive failure mechanism and the evolution law of a seismic slope, the adverse effect of progressive failure on slope stability is clarified. According to the progressive failure process of a slope under dynamic load, the strain-softening model and vibration deterioration model are introduced to represent the attenuation law of rock strength parameters, and a calculation method of seismic slope stability coupled with vibration disturbance and progressive failure is proposed. The method considers the strength parameter characteristics of a rock-soil mass in different stages and is combined with the vector sum method to obtain the time-history curve of the slope safety factor under earthquake action, which makes the evaluation result of slope stability more accurate and reliable. The numerical examples show that this method can effectively reflect the dynamic stability of seismic slopes, and solve the problem that the traditional calculation methods are difficult to characterize the strength attenuation characteristics of rock and soil mass. If these characteristics are not considered, the calculation results will be unsafe.

Slope stability calculation method for highwall mining with open-cut mines

Slope stability is a prominent problem for the efficient application and promotion of highwall mining technology, especially when mining residual coal under high and steep end-slope conditions. This study proposes the concept of target time pillar strength based on the required coal pillar service time. Creep tests were performed to measure the time-varying properties of coal shear strength parameters under different loads, and a time-varying function was established by regression. The highwall mining length is divided into three categories based on discontinuous structural plane theory, including goaf, yielding, and elastic zones, all of which are considered to have resistances against shear stress. The basal coal seam is prone to weakening owing to the weight of overlying strata, which may shift the slope failure mode from circular to sliding along the weak layer. Numerical modeling was used to study the influence of the bearing stress and target time strength on the development of the yielding zone at the coal pillar ribs. The coefficients of the three zones were determined, and the temporal and spatial evolution patterns of the shear strength parameters of the weak layer were acquired. A slope stability calculation method is proposed based on rigid body-limit equilibrium theory that can quantify the influence of highwall mining operations on slope stability, which is significant for popularizing highwall mining technology.

Calculation Method of Voltage Stability Based on Neural Network

With the deepening of the research on voltage stability(VS), the methods for analyzing VS have also been further developed. Although the probability of voltage collapse has been greatly reduced compared to before, the research on VS has always been a hot topic due to the seriousness of its consequences. This paper studies the sensitivity method of VS and other related calculation methods, corrects the power system through BP neural network, compares the load margin values obtained by the VS calculation method before and after the correction, and finds that the load margin obtained by the BP neural network algorithm proposed in this paper degree value error is minimal.

Traffic Safety Assessment of Highway Abnormal Indivisible Load Transport under Smoke-Free Regulations

A high proportion of truck drivers have smoking habits, especially for long-distance truck drivers, 90% of which have the habit of smoking. In recent years, some regulations are launched focus on the smoking behavior of drivers in the driving process. And the policies forces drivers to abandon the smoking habit. Abnormal indivisible load transport is crucial to the sustainable development of highway safety. In order to scientifically and effectively evaluate the traffic safety of highway abnormal indivisible load transportation, on the basis of extensive investiga of large transportation enterprises and management departments, combined with the method of UAV tracking and shooting video, the traffic variation features of outer profile size, load, dynamic characteristics and trajectory of abnormal indivisible load transport vehicles are obtained. Firstly, the meaning of abnormal in-divisible load transportation is defined. The traffic safety assessment of abnormal indivisible load transport is studied from the aspects of road accessibility and operation safety. Secondly, by ana-lyzing the jacking-up failure of abnormal indivisible load vehicles on convex curves, the sweeping space of the horizontal alignment, and rollover side slip conditions cross section, the road accessibility evaluation model of abnormal indivisible load vehicles under different highway alignment conditions is proposed. Thirdly, based on a certain binding strength, the constraint conditions for preventing the transverse and longitudinal sliding of the cargo are proposed, and the stability calculation method of the collapse point of the hydraulic trailer is determined. Finally, the feasibility and practicability of the safety evaluation method is verified by taking abnormal indivisible load transportation in Sichuan Province as an example. The achievements will lay a foundation for the necessary guidance of sustainable highway transport management. With the application of these technologies, the safety of abnormal indivisible load transport under smoke-free regulations can be guaranteed.

Mechanical problems for the long-term stability of rocks surrounding deep level underground tunnels

Based on the research of Academician Tan Tjong-Kie on the long-term stability mechanics of underground tunnel and considering Academician Sadovsky’s structural hierarchy theories on complex geological rock masses, the inherent statistical mechanical properties of inhomogeneous structure and closed stress in deep rock masses were investigated. Two mechanical problems were mainly studied, i.e. characteristics of inherent non-uniform deformation and closed stress of rock masses, and long-term stability of deep tunnels. The quantitative mathematical characterization of inherent non-uniform deformation and closed stress of rock masses were given using the method of statistical mechanics. Based on the law of mass conservation, a general calculation method of long-term stability and deformation of rock masses surrounding deep level tunnels was proposed. The Maxwell model was used to calculate the threshold of splitting. A post-peak failure model of rock was established to estimate the in-situ stress at which rock undergoes post-peak failure. With the help of the theory of the hirerachical structure of rock masses, the maximum value of rock displacement due to splitting dilatation was obtained. A dimensionless energy factor was introduced to define the extent of zonal disintegration of surrounding rock masses. It was concluded that the splitting and dilatancy deformation is the main part of the deformation of surrounding rocks. The reasons why unloading splitting failure is more likely to take place in rock masses surrounding deep level tunnels were explained. The split evolution pattern of rock masses surrounding deep level tunnels and the calculation method of dilatancy displacement were obtained. The calculation results of the range of loosening zone, the location of the rupture zone in rock masses surrounding deep level tunnels, and the displacement of the sidewall were compared with the existing monitoring data in the underground powerhouse of the Jinping Ⅰ Hydropower Station, and the agreement is good.

Power Stability Analysis and Evaluation Criteria of Dual-Infeed HVDC with LCC-HVDC and VSC-HVDC

This paper analyzes the power stability of the hybrid dual-infeed high-voltage direct-current (HVDC) system containing a line commutated converter-based HVDC (LCC-HVDC) and a voltage source converter-based HVDC (VSC-HVDC). First, the concept and the calculation method of power stability for the hybrid dual-infeed HVDC system are introduced. Second, the influence of VSC-HVDC on the power stability of the system is investigated. Third, the relationship between the power stability and the effective short circuit ratio (ESCR) is discussed under different system parameters. Then, the value range of the critical effective short circuit ratio is determined. Finally, the evaluation criteria of power stability are proposed. The results show that the evaluation criteria of the single-infeed LCC-HVDC system can still be used, if the VSC-HVDC is in constant AC voltage control mode; if the VSC-HVDC is in constant reactive power control mode, the hybrid dual-infeed HVDC system cannot operate stably when the ESCR is less than 2.0 and can operate stably with high power stability margin when the ESCR is greater than 3.0. The ESCR index can still be used to measure the power stability of the hybrid dual-infeed HVDC system.

Stability analysis and repair of a garbage dam

Garbage dam is an important structure of sanitary landfill, but there is no systematic stability calculation method at present. In this paper, the present situation of a garbage dam is investigated in detail, and it is found that the local settlement of the dam body is large, and there is the possibility of instability. Then, the soil samples were collected from the dam body and the indoor geotechnical tests were carried out. Based on the test data, the GEO-SLOPE software is used to carry out the numerical simulation analysis of the garbage dam. The results of the numerical analysis show that the safety factor of the garbage dam does not meet the requirements of the code, and there is a risk of instability. In view of the problems existing in the dam body, this paper puts forward the solutions for the reinforcement of the dam body, which effectively eliminates the problems of Seepage Damage and crack damage. The results show that the numerical analysis is correct and the reinforcement effect is effective.

Simplified Calculation Method of Wharf Bank Slope Stability Considering Old Piles

Based on the requirements of durability, a simplified calculation method of wharf slope stability considering the anti-sliding effect of old piles is derived according to the allowable cracks of old piles. Firstly, the acting force between the sliding soil and the pile is assumed to be distributed in a triangle, and the position of the resultant force of each pile is determined. According to the maximum crack width limit of the old pile, the maximum bending moment that the old pile can bear is calculated. According to the maximum bending moment, the maximum horizontal force at the mud surface, where is the slip arc position, can be inversely calculated, then the maximum anti-sliding force provided by the old piles can be obtained, and the stability of wharf bank slope considering the anti-sliding effect of the old piles is checked. In the slope stability calculation of Beira fishing wharf reconstruction project in Mozambique, the simplified calculation method considering the anti-sliding effect of old piles is adopted. The stability coefficient of wharf bank slope meets the requirements, and the extra treatment of bank slope is cancelled, which saves the project investment and construction period.

Stability analysis of double V-shaped gully embankment: dimension-reduced calculation method

Slope stability is generally analyzed by a two-dimensional (2D) method, ignoring the spatial effect (SE), which no longer meets the evaluation accuracy requirement. This problem is particularly prominent for embankments built on double V-shaped gullies (E-DVSG), which is a typical but unique topography in mountainous areas. Moreover, the technical requirements for engineers will increase sharply if a three-dimensional (3D) slope stability calculation method is adopted. To tackle this issue, pragmatically, a dimension-reduced slope stability analysis method (DR-SSAM) considering the SE of the E-DVSG was proposed and verified by a case study. Specifically, the DR-SSAM obtained the 3D safety factor of the E-DVSG by using the spatial effect curves and the safety factor from the 2D model. The results showed that this method was rational and efficient for engineering applications. In addition, the SE generation mechanism and condition, along with the influences resulting from the major factors, were addressed thoroughly.

Study on the Difference of Stability Calculation Between Numerical Simulation Analysis and Limit Equilibrium Methods--Take Huangmuya Landslide as an Example

Numerical simulation analysis and limit equilibrium methods are usually used in landslide stability analysis. In order to study the differences of calculation theory and results, this paper takes Huangmuya landslide as a case study. The field geological survey and exploration are used to determine the form and property of the landslide. The deformation characteristics and stability state are comprehensive analyzed based on the information of macroscopic inspection and professional monitoring data. It is considered that the potential slip zone of the landslide has not obviously deteriorated, and the induced formation mechanism of the landslide mainly comes from the process and deformation of the upper slip mass. Through the analysis, FLAC3D is applied to simulate the stability of Huangmuya landslideis. The numerical simulation results show that the displacement of the slope will further increase, mainly concentrated in the middle and leading edge of the slip mass. Besides, stability coefficients are calculated by five limit equilibrium methods. The relationship of stability coefficients is as follows: transfer coefficient method > Low method > US Army Corps of Engineers method > M-P method > Janbu method. Based on the numerical simulation results, it is recommended to give priority to the US Army Corps of Engineers method, Low method or M-P method as the stability calculation method because the deviation amount is all within±2%.

Study on calculation method of stability for embedded penstocks with stiffener ring under external pressure

A three-dimensional FEM(finite element model)is established, including penstocks with initial defect (ovality), backfill concrete, drainage cushion and surrounding rock. The nonlinear static calculation of the model is carried out. The stability of penstocks with backfill concrete, drainage cushion and surrounding rock under external pressure is studied. The sensibility of the embedded penstocks to initial defect, initial gap and elastic modulus of drainage cushion is analyzed. The results of finite element method, Jacobsen method and strength formula in SL281 are compared and analyzed. The results indicate that the FEM of penstocks, backfill concrete and surrounding rock with initial defects is easy to converge by nonlinear calculation; the ovality and gap have little influence on the critical external pressure of the embedded penstocks with stiffener ring, while the drainage cushion has a certain influence on the critical external pressure; the critical external pressure calculated by SL281 is low and safe; compared with Jacobsen method, the critical external pressure of the finite element method is increased by about 14%; for the embedded penstocks with drainage cushion, the finite element method can be used to calculate the influence of the drainage cushion on the critical external pressure, and the appropriate reduction factor can be obtained, and then the Jacobsen result can be modified by the reduction factor.

Study on stability calculation method of red clay slope based on composite sliding surface

The stability of the red clay slope is poor, and the long-term exposure to the atmospheric environment is prone to instability and damage due to the dry-wet cycle. The simplified Bishop method to calculating the stability of the red clay slope is inconsistent with the actual situation. The failure characteristics and mechanism of the red clay slope are analyzed, and the existing problems of the red clay slope stability calculation are pointed out. The red clay slopes in Guizhou Province are dominated by shallow failures. Local collapse and collapse failures are very common. Overall destruction is relatively rare. A stability analysis method for red clay slopes based on composite sliding surfaces (fold-line - circular arc) is proposed. In the stability analysis of clay slope, the soil body is divided into three layers of upper, middle and lower fissure areas, and different strength indexes are selected in different areas. It is recommended to consider the effect of hydrostatic pressure generated by the water column in the fracture on the stability of the red clay slope.

Generalized Numerical Differentiation Method for Stability Calculation of Periodic Delayed Differential Equation: Application for Variable Pitch Cutter in Milling

This paper proposes a generalized numerical differentiation method for stability prediction of the non-autonomous delayed differential equations (DDEs) with periodic coefficients and discrete delays. Firstly, the periodic DDE is described in state-space form and the period of a system is equally discretized. Then, the discrete first derivatives versus time are approximated by a linear combination of the state function values at multiple neighboring sampling grid points based on the finite-difference formulas. Such that, the original DDE is approximated as a series of algebraic equations and the Floquet transition matrix can be constructed on one period. At last, the system stability is determined according to the Floquet theory by checking the eigenvalues. The delayed damped Mathieu equation is regarded as a typical case to verify the effectiveness and efficiency of the presented method. The stability diagrams and rate of convergence are computed in comparison with those via the benchmark algorithm (the semi-discretization method). As an application, the presented method is used to predict the stability of milling with variable pitch cutter, and the computational result agrees well with the experimentally verified example.