Anchored stabilizing piles (ASPs) are now extensively applied as an effective method in landslide treatment, but systematic studies ASPs in landslides are still lacking. The behavior of the ASPs in landslide during progressive loading was analyzed through a 1:50 similitude ratio model test, including the earth pressure, bending moment, shear force, distributed load, and anchor tension. Furthermore, a validated numerical model by the model test results in terms of the pile bending moment, anchor tension, and earth pressures behind the pile was utilized to conduct a parametric study of ASPs, including the embedded lengths of the pile, initial prestress of the anchor, and number of anchor levels. The results show that the landslide thrust distribution behind the piles changes from a rectangular shape to a parabolic shape with a large top and a small bottom during landslide evolution. The maximum positive bending moment occurs near the sliding surface. The variations in maximum positive bending moment and anchor tension all show three distinct phases: stable, rapid growth, and slow increase. The combined retaining mechanism of the stabilizing piles and anchor can be summarized as follows: the landslide thrust is mainly carried by the pile initially, and the anchor tension is gradually mobilized with increasing earth pressure to share the landslide thrust together with the pile and transferred to stable bedrock to ensure the stability of the landslide. The findings of this work are helpful for verifying and improving the present design of ASPs in landslide treatment.

Experimental and numerical studies on the behavior and retaining mechanism of anchored stabilizing piles in landslides

This study aims to verify the suitability and reinforcement behavior of newly designed bored piles with retaining walls (BPRWs) for cutting-slope stabilization in the Tibet Plateau. As the first BPRWs prevention works in the alpine and hypoxic areas, full-scale performance testing is conducted of the high cutting slopes along the Lhasa-Nyingchi Railway under construction. Amid the construction processes of slope excavation and BPRWs installation, the overall structural performance, including lateral displacement, bending moment and lateral earth pressure, was determined to evaluate the cutting-slope stability and retaining mechanisms of BPRWs. The monitoring parameter distribution rules were thoroughly analysed. The relationship between the lateral earth pressure and pile displacement was studied, and a soil resistance calculation model was proposed. Finally, the BPRWs suitability was assessed. The results revealed that the retaining behaviour of BPRWs is closely related to the construction process. The displacement rate over time is characterized by alternating peaks and valleys, and the maximum displacement rate and bending moment occurs at the retaining wall pouring stage. The bow-shaped bending moment distribution with the pile depth exhibits low values on both ends and a high value in the middle. The ground reaction coefficient is allometrically attenuated with increasing lateral displacement. The proposed soil resistance model can satisfactorily predict the lateral earth pressure. The BPRWs deformation satisfies the service requirements at the construction and service stages. This case study provides a reinforcement reference for BPRW in alpine and hypoxic areas.

Full-scale performance testing of bored piles with retaining walls in high cutting slope

The invention discloses a zero-expansion dot matrix cylindrical shell structure used for a spacecraft and a design method thereof. According to the zero-expansion dot matrix cylindrical shell structure, a zero-expansion planar structure (5) is curved to form a cylinder, the zero-expansion planar structure (5) is obtained by spatially translating and interconnecting multiple zero-expansion basic cells (4) on a plane, each zero-expansion basic cell (4) is obtained by connecting four same micro-structures(3) at a top point, every two adjacent micro-structures (9) in each basic cell (4) are perpendicular to each other, and each micro-structure (3) is a triangle composed of a bottom edge (1) and two bevel edges (2). When the zero-expansion dot matrix cylindrical shell structure is designed, two different types of metal materials are selected to respectively serve as the material of the bottom edges (1) and the material of the bevel edges (2); then geometric dimension of the microstructure (3), the height and diameter of the zero-expansion dot matrix cylindrical shell structure (6), the number of basic cells in the annular direction, the number of basic cells in the height direction, the length of each bottom edge (1), the length of each bevel edge (2) and the section shape are designed in sequence; a finite element method is adopted for simulation; and a final design scheme is obtained through adjusting the length of each bottom edge (1) and the length of each bevel edge (2).

Zero-expansion dot matrix cylindrical shell structure used for spacecraft and design method thereof

In geotechnical engineering, ground movement caused by excavations is a challenging issue. The excessive differential settlement generated by soil movement induced by wall deflection may cause damage to nearby structures. A detailed literature review on the general deformation behavior of deep excavation support systems is presented in this paper. Many factors, such as normalized horizontal deflection (δh-max/He%), vertical displacement (δv-max/He%), δvmax/δhmax ratio, settlement influence zone (Do), etc., can play significant roles in describing the deflection behavior of the excavation system. A descriptive analysis of the reviewed data was carried out. The concluded δh-max/He% values range between 0.17 to 1.5, with a mean value of 0.58 for soft clay, while in the case of sands and stiff clay soils δh-max/He% value ranges between 0.07 to 0.40, with a mean value of 0.20. δv-max/He% values range between 0.13 to 1.10, with a mean value of 0.49 for soft soil, while its value ranges between 0.02 to 1.10, with a mean value of 0.24 in the case of sands and stiff clay soils. The settlement influence zone (Do) reaches a mean distance of 2.3He, which falls within Do=1.53.5He in the case of soft clays, while Do reaches a mean distance of 2.0He and 3.0He in the case of sands and other stiff clay soils, respectively. The relationship between system stiffness and excavation-induced wall and ground movements was discussed. Unfortunately, the literature review offers limited data regarding system stiffness, the 3-D nature of excavation support systems, excavation processes, and time effects.

General deformation behavior of deep excavation support systems: A review

Stability analysis of the pile-prestressed anchor composite structure based on failure mode

Field measurements and numerical studies of the behaviour of anchored sheet pile walls constructed with excavating and backfilling procedures

The invention relates to a vibration damper for a photonic crystal with an adjustable cell property period array. According to the vibration damper, the influence of a photonic crystal weak joint interface (or interface layer) on a band gap is considered, the controllability of physical and mechanics parameters under magnetorheological elastomers field conditions is utilized, an appropriate mechanism is built, and a controllable cell material physical property and interface layer geometrical parameters are obtained, so that the random vibration control photonic crystal variable band gap range suitable for multiple working condition control structure system obtained in a photonic crystal mechanism is realized, and the vibration damping efficiency of structural vibration control is improved.

Vibration damper for photonic crystal with adjustable cell property period array

Three-point bending experiments of concrete beams were conducted under the strain rate range of 10−6 s−1 and 1.5 × 10−3 s−1. A novel 3D laser scanner, Handy SCAN, was employed to detect the areas of interface, mortar and aggregate on the crack surface after the experiment. In this paper, the inhomogeneity of materials and the inertial effect were considered as the main factors in the strength enhancement of concrete together with a proposed dynamic model. With the obtained experimental results, the initial elastic modulus and tensile strength of concrete showed obvious rate sensitivity. Moreover, an empirical relationship of dynamic increase factor and strain rate was established for the strain rate range of 10−6 s−1 and 1.5 × 10−3 s−1. The contributions of aggregate and inertia effect to the dynamic enhancement of concrete strength were quantified with respect to the loading rate. The rate effect of concrete obtained by the experiments was verified by the finite element analysis on the mesoscopic scale with the model built by the three-dimensional random aggregate software.

https://www.mdpi.com/1424-8220/20/21/5994/pdf

Wenhu Zhao

Papers

Field measurements and numerical studies of the behaviour of anchored sheet pile walls constructed with excavating and backfilling procedures

Vibration damper for photonic crystal with adjustable cell property period array

Effect of Loading Rate on Tensile and Failure Behavior of Concrete.