Slope Displacement Research Articles

Postfailure Characterization of Shallow Landslides Using the Material Point Method

Although the mechanisms of slope failure caused by rising groundwater have been widely investigated, the kinematic behavior of landslides in the postfailure stage, which contains essential information for hazard mitigation and risk assessment, has not yet been fully studied. Thus, in this study, a series of numerical simulations using the material point method (MPM) were conducted to analyze the kinematic behavior and soil movement of shallow landslides (infinite slope problems). First, the proposed MPM formulation was validated in a full-scale landslide flume test. The simulated results of final slope profile, runout distance, deposit height, shear band development, slope displacement, and velocity accorded with the experimental results, suggesting that the MPM can quantitatively simulate large deformations. A parametric study of shallow slopes with various hydrological conditions and soil hydraulic and soil mechanical parameters was then performed to assess the influence of the aforementioned factors on landslide kinematics. The simulation results indicated that mechanical behavior at the slope toe is complex; the multiple plastic shear bands generated at the slope toe were due to a combination of shearing and compression. The deposition profile of the slopes was significantly influenced by all input parameters. Among the aforementioned parameters, soil cohesion, location of the groundwater table, and saturated soil permeability most greatly affected runout distance in the sensitivity assessment. Soil friction angle had a minor influence on the kinematic behavior of the slope.

Research on the Early Warning Threshold of Slope Displacement Rate

Slope is affected by internal structure and external natural and human factors, and the evolution process is quite complicated, which makes it difficult to determine the early warning indicators of slope instability. In view of the complexity of slope deformation, this paper introduces similarity theory, collects and sorts out related engineering data and landslide data of slid slopes in the past, uses engineering analogy to propose a displacement rate warning threshold method, and verifies the effectiveness of this method with engineering examples.

Influence of ground motion duration on the seismic performance of earth slopes based on numerical analysis

Assessing the dynamic stability of earth slopes is an important topic in geotechnical engineering field. In this study, the duration effect on the seismic performance of a multi-layer earth slope is quantitatively investigated, using two pairs of ground-motion suites selected matching a scenario-based response spectrum and a design spectrum, respectively. The four ground-motion suites are selected from the NGA-West2 database, with each pair of suites exhibiting a consistent distribution of response spectra yet different distributions of significant duration. Numerical analyses using the selected ground-motion suites as input are then conducted for the earth slope implemented in FLAC. Comparative results indicate that as compared to the shorter-duration suites, using the longer-duration ground-motion suites generally yields similar topographic acceleration-amplifications but an enlarged distribution of permanent slope displacements. Therefore, the influence of ground-motion duration on seismic-wave amplifications is insignificant; such influence on the earthquake-induced slope displacements is, however, significant. Using the selected longer-duration ground-motion suites, the slope (moderate) damage and failure probabilities exceeding specific displacement thresholds are increased by up to 20% and 50%, respectively. Therefore, when assessing the seismic performance of earth slopes in applications, one should pay adequate attention to the ground-motion duration effect, and input motions shall be selected in such a way that the duration characteristics of ground-motion records are properly constrained.

The Influence Law of Multi-point Cumulative Blasting in Slope

In order to study the cumulative blasting stress wave produced by the vibration of soft rock slope, the deformation regularity of the influence of blasting, caused by the horizontal and axial acceleration along with other additional stress waves were analyzed. The vibration displacement formula along with the vibration source stress wave superimposed model were established. The research also deduced the deformation rule for the gangue slope of Lijiahao Coal Mines as a vibration signal recorder was used to collect the blast vibration wave and the simulated analysis of displacement monitoring profile of the X and Y displacement rule under the influence of blast vibration were obtained. The results indicate that with the increase of the shot point distance, the displacement in the Y direction shows a logarithmic decline rule while the change in displacement of the X direction is small. The result also shows that the greater the initiation of multipoint shot firing, the greater the slope deformation and displacement of the rock mass and as a result multipoint nonsimultaneous blasting and control detonation time difference, can effectively reduce the effects of vibration on the slope deformation.

Comprehensive monitoring of talus slope deformation and displacement back analysis of mechanical parameters based on back-propagation neural network

Landslides are regarded as significant geological hazards across the world, causing serious economic losses and casualties. The understanding on deformation characteristics and failure mechanisms of landslides plays the vital roles in slope stability evaluation and reinforcement design. In this study, the deformation characteristics and failure mechanism of the Xiaomiaoling talus slope were analyzed based on field monitoring data. In addition, as it was difficult to measure the shear strength parameters of the rock–soil mixture due to its complex spatial structure and variable material composition, a displacement back analysis based on the back-propagation neural network (DBA-BPNN) was proposed to determine the shear strength parameters of the rock–soil mixture. The analytical results show that deformation of the Xiaomiaoling talus slope was that of a typical traction landslide, which has the characteristics of progressive failure, and major slope deformation was triggered by excavation and rainfall. According to field monitoring data, the shear strength parameters of the rock–soil mixture could be determined. The predicted cohesion and internal friction angle of the rock–soil mixture were 10.84 kPa and 19.51°, respectively, and the predicted and test values were in good agreement. The method proposed in this paper can provide references for the design and construction in geotechnical engineering.

Probabilistic evaluation of the seismic stability of infinite submarine slopes integrating the enhanced Newmark method and random field

For evaluation of the seismic stability of submarine slopes, traditional deterministic methods may not reflect the actual situation due to the uncertainties in input values such as seismic acceleration, soil properties, and hydraulic conditions. In this study, probabilistic analyses were conducted based on the use of an enhanced Newmark method to evaluate the seismic stability of submarine slopes. In the probabilistic workflow, the infinite slope model was used, whereby the spatially varied strengths of marine sediments were simulated by non-stationary random fields discretized by the Karhunen-Loeve expansion. The positions of the potential slip surfaces were searched automatically, rather than being predefined as in the traditional limit equilibrium method. Artificial earthquake accelerations, exhibiting the same spectral characteristics, were simulated as the input ground motions in the probabilistic analysis. The pore water pressure generation and dissipation models were incorporated into the enhanced Newmark method when calculating the permanent displacements of the submarine slopes. Monte Carlo simulations were conducted for statistical characterization of the slope displacements and their failure probabilities. The results of the analysis indicate the superiority of the probabilistic framework and demonstrate the significant effects of pore water pressure and the spatial variability of the soil strength on the displacements and failure probabilities of submarine slopes.

Application of multiple combination retaining structures on high slope

With the increase of the height of the filled slope, the application of multiple combination retaining structures (MCRS) is becoming more and more popular. However, the traditional design methods seldom consider the coupling effects between the substructures. To investigate the interaction of MCRS, this paper takes the filled slope project of a middle school in Quanzhou City, Fujian Province, China as an example. The filled slope was supported by MCRS, including reinforced soil, doublerow piles, anchors and counterfort retaining walls. The simulate procedure mainly included the following process: first, the MCRS model was established, then the mechanical response of the MCRS when replacing the fill materials and increasing the length of the rear row piles were obtained, and a comparative analysis was carried out. The following conclusions could be drawn: (1) The properties of backfill material have a significant impact on the displacement of backfill slope, and when the backfill is gravel soil, the displacement of slope can be controlled to a satisfactory degree. When the back-fill soil is replaced by silty clay, the shear strength and internal friction angle of soil become smaller, thus the displacement of slope increases significantly, which may lead to slope failure. (2) When the anchorage length is satisfied, increasing the length of the rear row pile has no significant effect on reducing the displacement of MCRS slope, but it can effectively reduce the axial force of anchor rod. (3) In MCRS, each substructure has complex interaction, and numerical simulation provides an effective means for accurate evaluation of MCRS.

Reservoir bank slope stability prediction model based on BP neural network

Safety monitoring and stability analysis of high slopes are essential for construction of concrete dam in precipitous gorges or mountainous areas. The estimate of slope stability is a difficult engineering shortcoming with a number of variables. Thereafter, a hybrid model of Support Vector Regression (SVR) and Teaching–learning-based optimization technique (TLBO) is proposed to develop the predicting function. TLBO was used in obtaining the best SRV factors to improve the prediction accuracy. Few essential factors, such as the installation height of instruments, classification of rock masses, modulus of elasticity, the complete measuring time cycle, the excavation height of slope, the start measuring time, and the actual excavation height after measurement are considered as the input parameter, but the slope displacement is regarded as output. The outcomes showed SRV-TLBO a reliable hybrid accurate prediction of slope stability, then it was effectively used to the left abutment slope of Jinping I hydropower station located in Yalongjiang concrete dam reservoir as a novel method for this purpose.

Study on Dynamic Characteristics of Loess Slope Reinforced by Prestressed Anchor Cables Under Earthquake

As a commonly used method to reinforce slopes, prestressed anchor cables can effectively prevent slope instability. To study the dynamic response characteristics of loess slopes reinforced with prestressed anchor cables under earthquake action. Taking a slope in Yan'an as an example, using MIDAS/GTS numerical simulation, a model of loess slope reinforced by prestressed anchor cables under earthquake action is established, and the dynamics are analyzed in terms of slope displacement, horizontal and vertical velocity, maximum principal stress, and anchor cable axial force. Based on the response characteristics, the influence of peak seismic acceleration and ground motion duration on the stability of loess slopes is analyzed. The results show that under the action of an earthquake, the range of displacement and velocity of the slope surface is larger than that of the inside of the slope, and the slope surface is more prone to instability. The seismic wave has little effect on the axial force of the anchor cable at the same elevation. The displacement of the slope increases with the increase of the seismic peak acceleration, and the input peak acceleration is every time With an increase of 0.1g, the deformation at the slope surface S5 increases by 0.014m, and the slope displacement changes significantly with the change of the duration of the ground motion, increasing continuously.

Erosion Control Treatment Using Geocell and Wheat Straw for Slope Protection

Slope failure triggered by soil erosion under rainfall remains one of the most difficult problems in geotechnical engineering. Slope protection with planting vegetation can be used to reinforce the soil and stabilize the slope, but the early collapse of the planting soil before the complete growth of plants becomes a major issue for this method. This paper has proposed a composite soil treatment and slope protection method using the geocell structures and the wheat straw reinforcement. The geocell structures improve the stability of the planting soil and provide a stable and fixed environment for the vegetation, while the wheat straw reinforces the soil and also increases the fertility. The authors have performed a total of 9 experiments in this work that are classified into three groups, i.e., the unsupported slopes, the geocell reinforced, and the geocell and wheat straw composite reinforced with a consideration of three different rainfall intensities. The progressive slope failure development during the rainfall was assessed, as well as the soil erosion, the slope displacement, and the water content. The results show that the slope failure increases as the rainfall continues, and the soil degradation increases with the intensity of rainfall. The soil treatment using geocell improves the slope stability, but the geocell and wheat straw composite reinforcement has the best erosion control and slope protection.

Analysis on construction stability of shallow tunnel with unsymmetrical pressure and small clear distance

Taking Georgia’s E60 Highway No. 3008 tunnel as the engineering background, a finite element calculation model was established for the construction stability of the shallow buried and unsymmetrical section of the tunnel exit, and the slope displacement and deformation and the construction dynamic characteristics of the supporting structure were analyzed. Finally, through analysis, the dangerous parts in the construction process are obtained. The analysis results show that: it is safe and feasible to simultaneously excavate the entrance section of the tunnel with unsymmetrical pressure and small spacing using the full-section method. The slope settlement process roughly goes through three stages: rapid change stage, slow change stage, stable stage, and the position stability of the slope toe is more sensitive to the overall construction of the tunnel. The maximum vertical settlement occurs at the position of the vault at the end of the tunnel, and more attention should be paid to this position during the construction. The research results can provide a certain theoretical reference for the construction of similar road tunnels in Europe.

Construction Stability Analysis of the Portal Section of Georgia’s E60 Highway Tunnel Based on Numerical Analysis

Combined with the construction of the No. 6 tunnel of the Khevi-Ubisa-Shorapani- Argveta section of Georgia’s E60 highway, the Midas GTSNX software was used to simulate the stability of the tunnel portal section during full-face construction. This paper analyzes the characteristics of displacement and stress variation of the tunnel portal slope during the whole section construction, the deformation law of surrounding rock during the whole section excavation, the deformation law of the initial support and final lining structure of the tunnel. The results based on the numerical simulation analysis show that when the entrance section of Georgia Tunnel No. 6 adopts full-face construction, the displacement of the supporting structure and the rock mass at the 5 m in front of the tunnel entrance changes greatly. Therefore, it is recommended to complete the invert construction of the tunnel before construction to ensure the safety of the tunnel entrance section; As for the entrance section as a whole, during the full-section construction process, the side slope of the entrance, the surrounding rock of the tunnel, and the supporting structure are all in a relatively stable state. Therefore, the full-section excavation of the No. 6 tunnel entrance section is safe and feasible.

Study on Dynamic Response Characteristics of Rock Slope

After the wenchuan earthquake, the dynamic response law of rock slope under the action of dynamic load is a very concerned and urgent problem in the field of seismic engineering. This paper analyzed the dynamic response law of simplified rock slope under the cosine wave dynamic load by numerical simulation with FLAC3D software. This research emphatically analyzed the variation law of amplification coefficient of seismic displacement, acceleration and velocity of rock slope under the condition of different slope height, slope angle, dynamic load period and dynamic load amplitude, which provides a basis for reducing seismic damage of slope area and seismic design of engineering structure.

Thermo-mechanical coupling analysis and software development

In order to quickly and accurately grasp the law of freeze-thaw reaction of permafrost slopes, based on the hydro-thermal-mechanical coupling theory, relying on MATLto compile a finite element program that can reflect the multi-field coupling mechanism of the soil. This test is in good agreement with the classic test, which verifies the reliability of the program. Based on this, the paper developed a set of water-thermal-mechanical coupling analysis software for permafrost slopes that can run independently and is easy to operate. The software?s functions and development process are introduced. The response characteristics of frozen soil slopes under freezing and thawing are analyzed in combination with the example papers. The results show that the slope temperature, moisture, stress and displacement are obviously different at different times. The maximum shear stress band appears at the freezing-thawing interface of the slope. The horizontal displacement of the slope is basically the same along the slope when the freezing is completed. At the end of the thawing period, the upper part and the lower part are large. The horizontal displacement and unfrozen water content of the slope during the thawing period are larger than those during the freezing period, but the maximum shear stress is small and the stability of permafrost in the warm season is poor. It has important application value for freeze-thaw calculation of frozen soil slope engineering.

RETRACTED: Analysis on deformation mechanism of high rock slope of hydropower station under complex hydrogeology

Currently, there are many defects in the method of analyzing the deformation mechanism of high rock slope of hydropower station, such as large analysis error, large deviation of horizontal displacement and vertical displacement of high rock slope. Therefore, this paper puts forward the deformation mechanism analysis method of high rock slope of hydropower station under complex hydrogeology. The elastic constitutive model, the brittle constitutive model and the yield and plastic constitutive models were constructed respectively. The failure mode of high rock slope of hydropower station under complex hydrogeology was analyzed. According to the geo-mechanical test, the deformation mechanism of high slope was analyzed. The results show that the error of horizontal displacement and vertical displacement of high rock slope calculated by this method is small, and the deformation mechanism of high rock slope of hydropower station can be analyzed accurately.

Investigation and mechanism analysis of disasters under Hokkaido Eastern Iburi earthquake

An Mw6.6 earthquake occurred at 3a.m. on September 6, 2018, in the eastern part of Iburi, Hokkaido. This earthquake killed 41 people, caused a series of service interruptions in Sapporo city. Soil liquefaction and approximately 6000 landslides were triggered. A field investigation was conducted on liquefaction and typical landslides during September 18 to 24, 2018. The liquefaction disaster exhibited soil flow, subgrade collapse, uneven settlement, earthquake subsidence, and deformation of buildings. After investigation of typical landslides, it was found that owing to the continuous heavy rainfall and typhoon, the surface soil had a high-water content. A layered loam of approximately 2 m below ground surface developed into a weak surface. Based on the analysis of sliding morphology, the landslides were classified into translational earth slides and earth flow. To clarify the mechanism of regional landslides, the stability and permanent displacement of slopes considering effect of continuous heavy rainfall and seismic motion was analyzed. Limit equilibrium analysis was applied based on the pseudo-static method. Then Newmark displacement calculation was conducted based on the seismic acceleration record. The distribution range of analysis results showed agreement with actual landslides disasters. The results verified the contribution of continuous rainfall and strong motion to the failure of regional slopes.

Deformation Prediction of Unstable Slopes Based on Real-Time Monitoring and DeepAR Model.

With increased urbanization, accidents related to slope instability are frequently encountered in construction sites. The deformation and failure mechanism of a landslide is a complex dynamic process, which seriously threatens people’s lives and property. Currently, prediction and early warning of a landslide can be effectively performed by using Internet of Things (IoT) technology to monitor the landslide deformation in real time and an artificial intelligence algorithm to predict the deformation trend. However, if a slope failure occurs during the construction period, the builders and decision-makers find it challenging to effectively apply IoT technology to monitor the emergency and assist in proposing treatment measures. Moreover, for projects during operation (e.g., a motorway in a mountainous area), no recognized artificial intelligence algorithm exists that can forecast the deformation of steep slopes using the huge data obtained from monitoring devices. In this context, this paper introduces a real-time wireless monitoring system with multiple sensors for retrieving high-frequency overall data that can describe the deformation feature of steep slopes. The system was installed in the Qili connecting line of a motorway in Zhejiang Province, China, to provide a technical support for the design and implementation of safety solutions for the steep slopes. Most of the devices were retained to monitor the slopes even after construction. The machine learning Probabilistic Forecasting with Autoregressive Recurrent Networks (DeepAR) model based on time series and probabilistic forecasting was introduced into the project to predict the slope displacement. The predictive accuracy of the DeepAR model was verified by the mean absolute error, the root mean square error and the goodness of fit. This study demonstrates that the presented monitoring system and the introduced predictive model had good safety control ability during construction and good prediction accuracy during operation. The proposed approach will be helpful to assess the safety of excavated slopes before constructing new infrastructures.

Erratum for “Procedure for Estimating Shear-Induced Seismic Slope Displacement for Shallow Crustal Earthquakes” by Jonathan D. Bray and Jorge Macedo

Erratum for “Procedure for Estimating Shear-Induced Seismic Slope Displacement for Shallow Crustal Earthquakes” by Jonathan D. Bray and Jorge Macedo

Determination of Creep-Induced Displacement of Soil Slopes Based on LEM

The creep of earth slopes is an important challenge of the long-term stability of slopes. This paper develops a limit equilibrium method (LEM)-based analytical approach for calculating the shear displacement of creep-induced failure surface in 2D state for all slices where both force and moment equilibrium equations are simultaneously satisfied as a new research. The relation between shear displacement and creep time is obtained with regard to visco-elastoplastic creep model. The overall safety factor is first calculated for the slip surface using Spencer method. Then, the shear displacements of all slices are obtained based on vertical displacement of crown and using displacement compatibility relation exists between slices. By combining force and moment equilibrium equations and assuming a zero resultant for inter-slice forces, the vertical displacement at crown is determined using visco-elastopastic creep model. A numerical model was developed to calculate slope displacement by the proposed method. Force and moment equilibrium equations are simultaneously satisfied by iteration technique. The proposed method is verified through two numerical examples comparing the new approach and conventional finite element method.

Geotechnical Analysis and 3D Fem Modeling of Ville San Pietro (Italy)

The paper describes the three-dimensional numerical model of Ville San Pietro, an Italian village subject to slope movements causing damage. The church (dating back to 1776), which is the most significant building of the area, is modelled too. The information from geotechnical and geophysical surveys on field are used to define the model geometry and the soil properties. A finite element code is adopted to simulate the slope behavior in occurrence of water table fluctuations, detected by piezometers, and to evaluate the slope displacements and stability. The validation of the model is carried out using the inclinometer and interferometry measures and by on-site inspections. The model demonstrated a good ability to simulate the slope behavior during the raising and lowering of the water table. The critical areas computed by the numerical code are in good accordance to the actual portions affected by soil displacements and damages. The modelling presented in this paper is crucial for future analyses that will take advantage of an innovative monitoring system, which will be installed on site.