Application of Kalman filter to reproduce displacement pattern along with the unknown soil properties of slow-moving landslides

<p><span>Landslides display heterogeneity in movement types and rates, ranging from creeping motion to catastrophic acceleration. In most of the catastrophic events, rocks, debris, or soil can travel at several tens of meters per year speed, causing significant cost in life losses, infrastructure, economy, and ecosystem of the region. In contrast, slow-moving landslides display typical velocities scaling from few centimeters to several meters per year. Although slow-moving landslides rarely claim life losses, they can still cause considerable damage to public and private infrastructure. Sometimes these slow, persistent landslides eventually lead to catastrophic acceleration, e.g., clayey landslides are prone to these transitions. Such events need to be detected by Early Warning Systems (EWS) in advance to take timely actions to reduce life and economic losses. Several approaches are proposed to forecast the time of failure; still, there is a need to improve prediction strategies and EWS’s. </span></p><p><span>Here we present state and parameter estimation for a simplified viscoplastic sliding model of a landslide using a Kalman filter approach, which is termed as an observer problem in control theory. The model under investigation is based on underlying mechanics (physics-based model) that portray a landslide behavior. In this model, a slide block is assumed to be placed on an inclined surface, where landslide (slide block) motion is regulated by basal pore fluid pressure and opposed by sliding resistance governed by friction, cohesion, and viscosity. This model is described by an Ordinary Differential Equation (ODE) with displacement as a state and landslide material and geometrical properties as parameters. In this approach, known parameter values (landslide geometrical parameters and some material properties) and water table height time-series are provided as input. Finally, two illustrative examples validate the presented approach: i) a synthetic case study and ii) Hollin hill landslide (Uhlemann et al., 2016) field data. </span></p><p><span>In both examples, displacement, friction angle, and viscosity are well estimated from known parameter values, water table height time-series, and displacement measurements. In the simulation results for the Hollin Hill field data, it is observed that friction angle almost remains constant while viscosity varies significantly through time.</span></p><p> </p><p><span>Uhlemann, S., Smith, A., Chambers, J., Dixon, N., Dijkstra, T., Haslam, E., Meldrum P., Merritt, A., Gunn, D., and Mackay, J., (2016). Assessment of ground-based monitoring techniques applied to landslide investigations. </span><em><span>Geomorphology</span></em><span>, 253, 438-451. doi:10.1016/j.geomorph.2015.10.027.</span></p>

Error of installation of a prismatic workpiece in the vise

The article analyzes the reasons why the workpiece is raised above the horizontal plane when it is fixed in the machine vise. The study is related to both the design of the device and the shape of the positioning of the workpiece surfaces. Five cases of the positioning of the side surfaces of the workpiece when fixed in a vise are considered. The role of backlash in the design of the machine vise in the installation error is determined. The values, by which the workpiece can rise after applying the tightening force in the case of errors in the shape of the workpiece and in the case of backlash in the design of the vise, are obtained. The values, by which the workpiece is raised, provided that there are no backlashes in the vise, are found when considering the tolerances for the positioning of surfaces depending on the method of cutting rolled products and the tolerances for the positioning of surfaces depending on the accuracy of rolled products. In addition, the values by which the workpiece is raised, provided that the workpiece does not have errors in the positioning of surfaces, taking into account the dimensional parameters of the slide bar and the guide of the vise with one movable jaw, as well as the dimensional parameters of the slide bar and the guide of the self-centering vise, are identified. The schemes for calculating the angle at which the slide block can turn due to the gapping in the guides and a scheme for calculating the height of the workpiece after fixing are presented. The geometric characteristics of the orientation of the workpiece after the application of the hold-down force are given; then the comparison of the results obtained in the study is carried out. As a result, it is concluded that the errors introduced by the design of the vise are several times less than the errors introduced by the shape of the workpiece. Methods for reducing the resulting installation errors are provided.

Discovery of the Baldy toreva near urban areas along the southern Wasatch Range, Utah

ABSTRACT Structural and geomorphic studies, and lithostratigraphic and biostratigraphic mapping reveal that a giant toreva block (6.125 km3) slid off Mount Timpanogos toward what are now densely populated urban areas along the Wasatch Front of Utah. The block forms a prominent peak known as Big Baldy, which consists of steeply dipping and locally brecciated limestone and quartzarenite over nearly horizontal shale. Preferential erosion of this shale below overlying limestone and quartzarenite cliffs is most likely the cause of this particular landslide and potential future slides along the Wasatch Front. The low-angle contact at the base of the giant toreva block was initially mapped as a thrust, then as a low-angle normal fault. In both cases, these faults were inferred to have large amounts of displacement (900 meters), but no traces of such faults are found in adjacent canyons. The Baldy slide is associated with geomorphologic features, such as faceted spurs, landslide scarps, sackungen, and hummocky terrain. Limestone and quartzarenite beds in the block are back-rotated up to 80° and are locally broken and brecciated. No evidence of hydro-fracturing is found in the breccia or of multiple brecciation episodes, which indicates surficial rather than deep-crustal processes and perhaps a single event of slip. We speculate based on structural reconstructions of the slide block, and interpolation of maximum downcutting rates on nearby streams, that the slide initiated between 700 and 500 ka. Discovery of the Baldy slide attests to the importance of recognizing the influence of surficial processes in mountain front development and demonstrate the ongoing geologic hazard of mass wasting to communities along the seismically active Wasatch Front and similar horst blocks.

A Modified Newmark Method for Calculating Permanent Displacement of Seismic Slope considering Dynamic Critical Acceleration

Newmark permanent displacement is an important index for evaluating seismic slope stability, which has been widely used in recent years. The traditional Newmark sliding method assumes that the critical acceleration is constant but does not consider the inhomogeneity and dynamic reduction process of shear strength on the sliding surface, presumably leading to underestimation of the permanent displacement. In this paper, this problem is analyzed, and a new method for calculating permanent displacement of seismic slope considering dynamic critical acceleration is proposed, in which the Monte Carlo simulation is used. Example calculations indicate that this approach permits to show the dropping cohesion and the dynamic critical acceleration of the slide block during the earthquake time history. The improved method for calculating seismic slope permanent displacement presented in this paper solves the problem that the calculated value from the Newmark sliding method is smaller than the real value and is a useful improvement.

Design of the Fall-Block Sensing of the Railway Line Pantograph Based on 3D Machine Vision Sensors

As an important part of the electric locomotive in railway transportation, the sensing and inspection of the pantograph has a significant effect on the safe operation of the train. In general, the pantograph carbon slip detection items include slide wear detection, slip strip crack detection, carbon slip fall-block detection and slip strip wear detection. The emergence and development of structured light measurement technology with 3D sensors provide new technical means for the acquisition of spatial 3D information. The three-dimensional data can not only obtain more information but also reduce the data deviation, thereby improving the measurement accuracy and work efficiency. At present, few studies have been conducted on the slide block and partial wear of the carbon slide. Therefore, this paper studies the detection of the pantograph slide block based on 3D sensor measurement technology. The experimental results indicate that it is feasible to adopt 3D measurement technology to detect the fall-block of the pantograph slide. In addition, a sound detection effect can also be obtained.

Improved Structure of Intermediate Shaft Device of JC-300 Winch

JC - 300 winch is applicable to many transportation vehicles scheduling when loading and unloading of goods ,it also can be used for hauling heavy objects.but as the working process position of intermediate shaft opinion is uncertainty ,top phenomenon between slider and intermediate shaft pinion during the meshing process may be easily occurred,this will make the slide block jammed while the intermediate shaft pinion is unable to rotate properly.the paper propose to add guide wheels in intermediate shaft pinion and slide block respectively, and use ansys software to analysis the strength of guide wheel shaft after scheme feasible analysis.

Three-dimensional swimming robotic fish with slide-block structure: design and realization

SUMMARYThis paper focuses on the mechanism design of a slide-block structure and its application on a biomimetic modular robotic fish for three-dimensional swimming. First, as a barycenter-adjustor, the slide-block structure is integrated into a mechanical design of a robotic fish, which is constructed by a control module, a driving module, and a fan-shaped caudal fin. The three-dimensional locomotion of robotic fish is decomposed into two-dimensional locomotion in horizontal plane and ascent–descent locomotion in vertical plane. Both the kinematics of the horizontal swim and the dynamics of the ascent–descent swim are analyzed by the curve fitting method. Finally, experimental results validate the three-dimensional swimming capability of the robotic fish. Furthermore, the impact of two design parameters on the swimming capability of the robotic fish is discussed by the experimental method. The experimental results confirm that the robotic fish with one driving module and a fan-shaped low-aspect-ratio caudal foil can produce higher propulsive speed than other parameter combinations.

Preform and Die Designs for Hot Forging Process of Linear Slide Block

In this study, the preform and die designs of hot forging process were proposed for a long-flat slide block. This block is assembled to the linear slide for carrying the moving table. Three different billet geometry designs were proposed to obtain good die filling. The volume of the flash is limited to 30% with a flash thickness design in 3 mm. The forging die was designed with four ejectors to push up the forged part smoothly. The proposed billet geometries and die design were evaluated using CAE simulation. The simulation results indicated that the suitable perform design is able to achieve better material flow. The flash flow control is able to reduce the forming load and improve the die filling. The forging experiments were carried out to verify the proposed method, the experiment results showed good agreement with the CAE simulations. For the Improvement of wear and corrosion resistances of Inconel718 (In718) surface, high velocity oxygen fuel (HVOF) thermal spray coating of micron-sized WC-Cr-C-Ni powder was coated onto Inconel718 surface and laser heat-treatment of the coating was carried out. Porous coating of porosity 2.2±0.4% was prepared by HVOF coating, and it was improved by laser heat-treatment, reducing the porosity to 0.35±0.08%. Micro-hardness of laser heat-treated coating increased more than four times compared to the surface of In718. Friction coefficient decreased by HVOF coating and laser heat-treatment. Wear resistance improved, decreasing the wear depth by the coating and laser heating. The interface between coating and In718 was compacted, and elements diffused from both coating and inconel718 substrate to interface, forming metal rich buffer zone (interface) and enhancing the adhesion of coating. Corrosion resistance improved by coating in sea water 3.5% NaCl solution and in 1M HCl acid, but it worsened in 1M NaOH base. For the improvement of wear and corrosion resistances of Inconel718, HVOF WC-metal power coating and laser heat-treatment are recommended.