Monitoring-data mechanism-driven dynamic evaluation method for slope safety

Roundabouts are increasingly replacing conventional signalized intersections due to their potential to enhance traffic safety and operational efficiency. This paper examines and reviews the safety benefits, design considerations, and evaluation methods for roundabouts. Studies consistently show significant reductions in crashes at roundabouts relative to other at-grade intersection control systems, particularly severe injury crashes, with reductions ranging from 37% to 88%. Roundabouts reduce conflict points, lower vehicle speeds, and improve safety for both motorized and vulnerable road users. The methodology for this paper involved a comprehensive review of literature on roundabout design and safety evaluation techniques. Data from global studies were analyzed to identify key design elements such as geometric layout, signage, and pedestrian provisions, which contribute to roundabout safety. Various safety evaluation methods, including crash data analysis, traffic conflict techniques, and surrogate safety measures, were also assessed for their effectiveness in evaluating roundabout performance. Findings indicate that proper geometric design, clear signage, and the use of innovative features like right-turn bypass lanes and roundabout metering systems can enhance safety and traffic flow. Based on these findings, the paper recommends integrating these design elements, prioritizing the safety of vulnerable users, and utilizing advanced safety evaluation techniques, including simulation modelling and intelligent transportation systems (ITS) to further optimize roundabout performance.

Due to the serious condition of safety production in hydropower construction project on the whole, it is an urgent need to evaluate hydropower engineering construction safety. But the problem of the mapping relationship between evaluation index and accidents, fixed and variable weight, randomness and fuzziness and so on, can't be solved through the traditional safety evaluation method for hydraulic engineering construction safety. In that case centering on the construction process in hydropower project, safety evaluation indexes that construction couples with operation are established by introducing rough set theory, and then those indexes are simplified. Furthermore, the least evaluation index set and each coupled weight are determined in order to enable the evaluation method to have a feature of approximate function. Finally, the feasibility of this evaluation method is proved by empirical analysis. To sum up, this method is of theoretical and practical significance in safety evaluation for hydropower construction project.

From the viewpoint of BDS bridge displacement monitoring, which is easily affected by background noise and the calculation of a fixed threshold value in the wavelet filtering algorithm, which is often related to the data length. In this paper, a data processing method of Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN), combined with adaptive threshold wavelet de-noising is proposed. The adaptive threshold wavelet filtering method composed of the mean and variance of wavelet coefficients of each layer is used to de-noise the BDS displacement monitoring data. CEEMDAN was used to decompose the displacement response data of the bridge to obtain the intrinsic mode function (IMF). Correlation coefficients were used to distinguish the noisy component from the effective component, and the adaptive threshold wavelet de-noising occurred on the noisy component. Finally, all IMF were restructured. The simulation experiment and the BDS displacement monitoring data of Nanmao Bridge were verified. The results demonstrated that the proposed method could effectively suppress random noise and multipath noise, and effectively obtain the real response of bridge displacement.

A Back Analysis Program System has been developed for geomechanics applications. The system inherits the developments made in the last two decades and adds new features to establish a multi-purpose back analysis program system to account for elasticity and elastoplasticity both from deterministic and stochastic viewpoints.The contributions made by previous researchers are systematically analyzed to categorize various factors considered in back analysis in geomechanics. A scheme which results from this analysis becomes a Back Analysis Classification Scheme. This scheme identifies seven different types of unknown data category combinations. The thesis uses these seven cases as a guideline to present the discussions.Firstly, the back analysis procedures are discussed for elasticity considering the unknown data categories M (Material), L (Load), and ML (Material and Load), respectively. These three cases deed with the most fundamental aspects of a force-displacement relationship. The use of stress measurements along with displacement measurements is identified as a necessary step to be taken for a stable estimation of load parameters, or simultaneous estimation of Young's moduli and load parameters.Secondly, the three ad hoc back analysis procedures developed for elasticity are extended to account for elasto-plasticity. Numerical examples show that the elasto-plastic versions of the back analysis algorithms work equally well for those cases in which the degree of nonlinearity is relatively mild.https://espace.library.uq.edu.au/js/fckeditor/editor/images/spacer.gifThirdly, the six back analysis algorithms and the two forward analysis modules developed for elasticity and for elasto-plasticity are coupled with Roseribrock's method to form the eight versions of deterministic Direct Search algorithms. By these algorithms, the other four types of unknown categories (G-eometry, GM, GL, and GML) which have not been otherwise accounted for, are covered. Benchmark analyses reveal that problems of all unknown data category types in elasticity and in elasto-plasticity are readily solvable by these Direct Search algorithms. However, practical costs involved remain high especially for a complex problem having unknown parameters in all categories in elasto-plasticity.Having completed a multi-purpose back analysis program system from a deterministic viewpoint, another eight versions of stochastic hybrid back analysis algorithms are added to the system by using the Bayesf method. This completes a brief description of the current form of the back analysis program system CAD AX. A simple scheme with which an efficiency of a measurement pattern may be quantitatively evaluated is introduced as the Measurement Grade System (MGS). To maximize the benefit of the MGS, an economical method of computing measurement efficiency is proposed as the Quick-Co-Variance Method.In addition to the library of the back analysis algorithms formulated for problems involving one load application process, the new algorithm DBAP ! Multiple-Stage is developed for problems involving more than one load application process (in this case, excavation). By this method, in-situ stresses can be determined by measurements taken from an arbitrary stage of excavation. This may be beneficial for those cases in which displacement or stress monitoring cannot be performed in the early stages of excavation due to practical restraints. This multiple-stage algorithm is coupled with general estimation methods to form Direct Search and Bayesian versions of DBAP I Multiple-Stage. These hybrid multiple-stage back analysis procedures are applied to various types of numerical examples in which the MGS and the QCV Method are used to perform comparative studies to evaluate the relative efficiencies of various measurement patterns.A localized investigation is performed with the MGS and the QCV Method to establish the fundamental measurement strategies to accurately estimate the Mohr-Coulomb parameters of a continuum and of a joint plane. The results of this study reveal that recommended orientations of measurements may be identified with respect to the directions of the principal stresses (for a continuum) or a structural feature (for a joint plane). The description of the applied back analysis procedures for elasto-plasticity is concluded by a simulation of the progressive characterization of rock mass properties and in-situ conditions in a staged excavation problem. This numerical example confirms various findings made in the thesis and presents a typical repetitive sequence of strategy establishment, measurement planning, and back analysis required for monitoring a staged excavation problem.The thesis is closed by reviewing the developments made and graphically illustrating those developments with the previous contributions . Figures provided in Chapter 8 show how the back analysis program system CAD AX has inherited the work of previous researchers and added new features to be in the current form. The areas for further improvements, exploration, and fie ld applications are graphically identified by those figures. Four major development directions are identified to conclude the presentation.

As the strength of road construction gradually increases and road networks tend to improve in mountainous areas, the safety of spoil ground slope has become an ecological and environmental problem that cannot be ignored. At present, especially under the dual control of basic farmland and ecological red lines, it is quite difficult to design a suitable spoil ground to meet construction needs. Spoil grounds are often overfilled. At present, safety evaluation is mainly conducted through field investigations and indoor calculations, which takes a longer time. It is extremely necessary to conduct quick safety evaluation and hazard mitigation on the spoil ground slope. Based on the data collection method, investigation and case study method and expert evaluation method, this paper establishes 18 evaluation indicators closely related to the safety of spoil ground slopes and assigns empowerments, forming a quick evaluation table for the safety of spoil ground slopes, and applies the table to the spoil ground slope on the Guiyang Huaxi-Anshun Expressway. The evaluation results indicate that the risk classification of the slope under normal conditions is high risk, while under rainfall conditions is extremely high risk. After slope stability calculation and comparison with the actual situation, the results are consistent, which indicate this quick evaluation table is suitable for safety evaluation of spoil ground slope.

Optimal design of anchor cables for slope reinforcement based on stress and displacement fields

A new method for preclinical evaluation of safety of antiarrhythmic drugs is proposed. During chronic stress, class I antiarrhythmic preparations increased mortality of test animals. By contrast, class II-IV antiarrhythmic agents and antioxidants produced no significant effect on mortality of experimental mice. These data agree with published results of multicenter studies.

Soil-rock mixture slope is a common type of slope in nature, which has obvious heterogeneity and discontinuity. Rheological property of soil is one of the main causes leading to the soil-rock mixture slope deformation and instability. But almost all the existing analyses on the stability of soil-rock mixture slopes neglect the rheological properties of soil. Using digital image processing technology, a soil-rock mixture slope model in the reservoir area of one hydropower station in China is built. Then the strength reduction method in FLAC3D code is adopted to analyze the slope stability. The analysis mainly focuses on the creep characteristics of soil and the effect of the creep parameters on the deformation and stability of the soil-rock mixture slope. The results show that the rheological property of soil can obviously reduce the factor of safety of the soil-rock mixture slope, increase the deformation of the slope, and adversely affect the stability of the slope. The creep viscosity coefficient has a great influence on the long-term stability of slope, and the greater the viscosity coefficient is, the lower the safety factor is.

Problems and flaws of existing safety criteria for vibration are reviewed. A simple consideration of particle vibration velocity cannot fully reflect the inherent law of effects of explosion earthquake on structures. Sometimes the occurrence of explosions exceeding the standard velocity for safety will not necessarily cause damage to structures and those below the standard velocity for safety may destroy structures. For this reason, the free vibration frequency of structures and the safety margin of the structure should be considered. Based on safe, practical and convenient conditions, that in respect of safety criteria for dike and slope exposed to vibration, two indicators, i.e., stability factor of dike and slope and vibration velocity of particle, can be used to determine the effect of vibration on them is proposed. That is to say, pseudo-static method is adopted to make vibration inertia force equivalent to a static force on slope bars and then strength reduction method or limit equilibrium method is used to calculate the safety factor, which can directly evaluate the stability of slope. In combination with the particle vibration velocity given in specifications, the safety of dike and slope can be determined. Lastly, specific engineering cases are used to validate the rationality of this criterion. This method can serve as a reference for similar projects

In landslide control engineering, anti-slip piles are the most commonly used means. This article established a numerical model of the interaction between fully weathered granite landslides and anti-slip piles based on the strength reduction method. Firstly, five pile-soil interaction models with different pile spacing were established using Abaqus software, and individual components were generated and assembled using the stretching function. The friction surface is used between the pile and soil, and the normal and tangential contact characteristics are both Penalties. Secondly, the strength reduction method based on displacement criteria is used to reduce the rock and soil parameters to the unstable stage before failure, while calculating the slope safety factor. Then, the influence of anti-slip pile spacing on slope stability, pile shear force, bending moment, and soil arch effect are studied. The strength reduction method and pile-soil interaction model used in this article can effectively avoid single pile effects and have high accuracy in characterizing soil arching effects. The results afford certain application and promotion values by providing theoretical references and technical guidance for similar anti-slide pile reinforced slope projects.

In order to fully understand the different effect of strength reduction method on slope stability analysis in different instability criterion, and solve the problems related to the instability of slope, this paper uses the platform of the finite element software ABAQUS to carry out the research that finite element strength reduction method analyzes the stability of homogeneous soil slope in different instability criterion. Moreover, in detail, this paper analyzes the difference between slope safety factor and the soil strength parameters change on the effect by using strength reduction method in different instability criterion. The research shows that by using the strength reduction method, the safety factor has been affected by different instability criteria, but its influence affected by the soil strength in a certain range of the parameters are decided, at the same time, soil cohesion, internal friction angle, Poisson ratio and other parameters for the development of the plastic zone and the shape of the sliding surface also have some influence on the critical state of the slope.

Engineers frequently use simplified seismic slope displacement procedures to evaluate the performance of earth structures and natural slopes. Current practices typically adopt Newmark‐type and semi‐empirical seismic displacement prediction models (SDPMs) to estimate the seismic slope displacements ( D ) based on ground motion intensity measures at a given hazard level. In a probabilistic framework, the full range of potential IM values and possible earthquake scenarios are utilized to estimate earthquake‐induced slope displacements for target hazard levels. This study outlines a methodology for deriving probabilistic D values for slopes in Greater Vancouver and the Lower Mainland, incorporating local seismic hazard sources and updates from Canada's 6th‐generation seismic hazard model (CSHM6). A novel computational tool, EqDisp, is developed and used, integrating probabilistic seismic hazard analysis with the calculation of probabilistic permanent displacements ( D ). The study streamlines the process of calculating probabilistic D values for specific locations and site classes, considering various slope characteristics and uncertainties inherent in SDPMs. Using EqDisp, displacement calculations are performed for 264 different sites across Lower Mainland and simplified regional equation is also introduced for direct estimation of the probabilistic displacement values. The significance of probabilistic approaches in generating displacement hazard curves and seismic landslide hazard maps is underscored, enhancing regional assessments of slope stability hazards.

Slope displacement is a crucial factor that affects slope stability in engineering construction. The monitoring and prediction of slope displacement are especially important to ensure slope stability. To achieve this goal, it is necessary to establish an effective prediction model and analyze the patterns and trends of slope displacement. In recent years, monitoring efforts for high slopes have increased. With the growing availability of means and data for slope monitoring, the accurate prediction of slope displacement accidents has become even more critical. However, the lack of an accurate and efficient algorithm has resulted in an underutilization of available data. In this paper, we propose a combined EEMD-IESSA-LSSVM algorithm. Firstly, we use EEMD to decompose the slope displacement data and then introduce a more efficient and improved version of the sparrow search algorithm, called the irrational escape sparrow search algorithm (IESSA), by optimizing it and incorporating adaptive weight factors. We compare the IESSA algorithm with SSA, CSSOA, PSO, and GWO algorithms through validation using three different sets of benchmark functions. This comparison demonstrates that the IESSA algorithm achieves higher accuracy and a faster solving speed in solving these functions. Finally, we optimize LSSVM to predict slope displacement by incorporating rainfall and water level data. To verify the reliability of the algorithm, we conduct simulation analysis using slope data from the xtGTX1 monitoring point and the xtGTX3 monitoring point in the Yangtze River Xin Tan landslide and compare the results with those obtained using EEMD-LSSVM, EEMD-SSA-LSSVM, and EEMD-GWO-LSSVM. After numerical simulation, the goodness-of-fit of the two monitoring points is 0.98998 and 0.97714, respectively, which is 42% and 34% better than before. Using Friedman and Nemenyi tests, the algorithms were ranked as follows: IESSA-LSSVM > GWO-LSSVM > SSA-LSSVM > LSSVM. The findings indicate that the combined EEMD-IESSA-LSSVM algorithm exhibits a superior prediction ability and provides more accurate predictions for slope landslides compared to other algorithms.

In engineering, due to the direct or indirect influence of a variety of other factors, lead to local anchor failure, thus forming a hidden danger of slope safety. Through the specific slope engineering case, the corresponding simulation model is established by using PLAXIS 3D to calculate the slope displacement and safety factor under different anchor failure conditions. At the same time of calculating the safety factor of slope stability, the displacement variation law of slope is analyzed, and the relationship curve between slope stability and displacement has been obtained. The results show that there is an obvious split zone in the unsupported slope, and the displacement of the slope is greatly improved after support. The closer the failed anchor is to the middle of the slope and the top of the slope, the less influence it has on the slope safety.

Almost all post-exploitation open pit mines in the world are shaped as a final water reservoir. One of the main hazards is the slope stability of lake banks. To develop a reliability methodology for assessing the long-term stability of flooded open-pit lake, a back analysis was conducted using 2D and 3D large-scale numerical models of Lake Most, which is one of the largest mining lakes in Europe (Czech Republic). The large-scale numerical model was built, based on the site observations, large scale LiDAR data, in situ characterisation tests, and statistical analysis of geotechnical data, on DTMs defining the complex geology of the site and on numerous piezometric levels to build the water table. Local and global safety factor (SF) were calculated using the strength reduction method. The results highlighted the reliability of the methodology to combine the geometric model with the geological model to create a large-scale numerical model, to identify local and potentially instable zones, and to highlight the role of a weak contact layer. The calculation of 3D SF has shown a very good correlation between the lowest SF and the ground movement observations noted by the Czech authorities.