Performance investigation of micropile groups in stabilizing unstable talus slopes via centrifuge model tests

Pei, Zhenwei; Zhang, Yanjun; Nian, Tingkai; Song, Xiaolong; Zhao, Wei

doi:10.1139/cgj-2021-0681

Cited by 5 publications

(13 citation statements)

References 26 publications

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“…Since the predisposing factors, such as the degree of RMD and RMD-related indices, change over time, the time-dependent susceptibility or risk of RMD-induced reservoir geohazards also can be determined. For the administration departments related with disaster mitigation and prevention, the above work will contribute to determining the order of priority when the risk control measures or treatments of some potential geohazards, such as multi-row stabilizing piles (Pei et al, 2022;Zhang et al, 2022;Zhang et al, 2023), are about to be implemented.…”

Section: Discussionmentioning

confidence: 99%

A photographic method to identify reservoir geohazards induced by rock mass deterioration of hydro-fluctuation belt

Dai,

Zhang,

Zhang

et al. 2024

Front. Earth Sci.

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Potential geohazards triggered by the rock mass deterioration (RMD) of the hydro-fluctuation belt (HFB) in the Three Gorges Reservoir area (TGRA) severely threaten the lives and property of people, it is necessary and urgent to timely identify this kind of potential geohazard. Aiming at this issue, several typical evolution modes of potential RMD-induced geohazards were generalized, and an unmanned aerial vehicle (UAV) photographic method integrating the orthophotography, three-dimensional multi-angle oblique photography and high-precision digital elevation model (DEM) was proposed to early recognize the newly formed potential RMD-induced geohazards. By resolving the problem of poor precision in the orthophotographic images of high steep bank slopes, the proposed method improved the recognition reliability of potential reservoir geohazards in the HFBs. Taking the bank slopes from Zigui County to Badong County as the study area, 116 new potential RMD-induced geohazard sites were identified by the presented approach, including 64 and 52 sites on the left and right bank, respectively. Through field verifications, 17 and 19 sites on the left and right bank were found to be consistent with existing hazards, indicating the effectiveness of the proposed approach in avoiding the false and missing recognitions of potential RMD-induced reservoir geohazards at current levels of knowledge and technology. The study can provide a valuable reference for the early identification of RMD-induced geohazards in reservoir areas.

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Section: Discussionmentioning

confidence: 99%

A photographic method to identify reservoir geohazards induced by rock mass deterioration of hydro-fluctuation belt

Dai,

Zhang,

Zhang

et al. 2024

Front. Earth Sci.

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“…The vital part of the model setup is the identification of contact parameters between the loose deposit and the bedrock (Slide). The parameters of contacts between the loose deposit and the bedrock are referred to in the setup of the centrifuge model test previously performed by Pei et al [20]. The direct shear test was conducted to measure the contact property between the bedrock and the loose deposit, and the results are close to that of the loose deposit, also obtained by the direct shear test.…”

Section: Numerical Simulation Settingsmentioning

confidence: 96%

“…The loose deposit of the talus slope usually consists of a soil and rock mixture, with the obvious discrete characteristics of discontinuities and non-homogeneity [20]. Compared with the finite element method (FEM), the discrete element method (DEM) is highly capable of modeling the discrete nature of granular materials.…”

Section: Discrete Element Modelmentioning

confidence: 99%

“…However, the contact between the bedrock and the particles cannot be performed by the JKR contact model, so a part named "Slide" simulated by discrete particles is added close to the surface of the bedrock to realize the contact between the bedrock and loose deposit (Figure 3c). The physical and mechanical parameters of the model are shown in Table 2 [20,27]. Notes: PD3D is a rigid cell with a single node, which represents a rigid homogeneous sphere with six degrees of freedom in translation and rotation.…”

Section: Numerical Simulation Settingsmentioning

confidence: 99%

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Cross-Scale Analysis on the Working Performance of Micropile Group and Talus Slope System

et al. 2023

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Micropile groups (MPGs), combined with the advantages of the anti-slip pile and anchor cable, offer an efficient support system that can be used as countermeasures for stabilizing the talus slopes. However, the performance of MPGs in stabilizing the talus slopes is rarely numerically investigated from the continuous-discontinuous viewpoints. To fulfil this knowledge gap, a numerical method coupled with the discrete element method (DEM) with the finite element method (FEM) is proposed first, and validated to be with good accuracy by the centrifuge model tests. A series of cross-scale analysis cases are then adopted to assess the behavior of MPG in the talus slopes, in which the influencing factors are also taken into account. The numerical results indicate that the MPGs reinforcement can significantly improve the stability of the talus slopes, avoiding the potential progressive shallow slip. For the MPGs with different pile spacing, the distribution laws of deformation and internal force are rather similar, but the one whose pile spacing is four times the pile diameter shows better performance. Moreover, the effective anchorage length of MPG is approximately 1/3 of the pile length, and the axial force distribution is influenced by the type of pile bottom constraint and the tangential contact between the micropile and the bedrock. Finally, the “bidirectional anchorage” attributed to the platform and the bedrock can greatly improve the performance of the MPG, which is a non-negligible part of the anti-slip mechanism of the MPG. This study is of great significance for facilitating the design of MPG in stabilizing the talus slopes.

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“…Studies have indicated that micropile groups provide effective support for seismic dynamic response in liquefiable soil conditions [26]. Simultaneously, micropile groups offer notable advantages in addressing sloping ground situations [27]. Their flexible reinforcement characteristics significantly enhance the soil's shear resistance, mobilizing the soil's resistance to pullout and sliding, thereby forming a combined support system that enhances the overall stability of a sloping terrain [28].…”

Section: Introductionmentioning

confidence: 99%

Horizontal and Uplift Bearing Characteristics of a Cast-In-Place Micropile Group Foundation in a Plateau Mountainous Area

Li,

Ren

2023

Sustainability

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Micropile groups have been progressively more frequently adopted in the construction of transmission tower bases due to their compact size and flexible construction advantages. However, the load-bearing characteristics and deformation mechanisms of micropile groups are complex, and the study of their coupling effects under combined loads remains unclear. Consequently, this paper presents a field static load test of micropile groups in a highland mountainous area. The analysis encompasses the axial force distribution and load-sharing ratio of micropiles. With a focus on micropile groups subjected to both uplift and horizontal combined loads, the coupled effects under different load combination ratios are examined using numerical simulation methods. The key findings are as follows: During the uplift loading process, the load distribution among individual piles is relatively uniform, with lower side friction resistance gradually coming into play to counterbalance the top load. The load–uplift displacement curve exhibits a steep characteristic, making it susceptible to sudden failure in practical engineering applications. Under the simultaneous action of uplift (V) and horizontal (H) loads, the unbalanced lateral frictional resistance on both sides of the pile segment induces additional bending moments, which is an important part affecting the load-coupling mechanisms. The uplift resistance capacity of micropile groups decreases with an increase in horizontal load, while the horizontal load-carrying capacity initially decreases and then increases with an increase in uplift load. The space enclosed by the yield envelope under combined load, and the vertical line of the ultimate load, is divided into a ‘failure zone’ and a ‘safety zone.’ In the design of the pile foundation, the uplift bearing capacity reduced by the ‘failure zone’ should be taken into account.

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Performance investigation of micropile groups in stabilizing unstable talus slopes via centrifuge model tests

Cited by 5 publications

References 26 publications

A photographic method to identify reservoir geohazards induced by rock mass deterioration of hydro-fluctuation belt

A photographic method to identify reservoir geohazards induced by rock mass deterioration of hydro-fluctuation belt

Cross-Scale Analysis on the Working Performance of Micropile Group and Talus Slope System

Horizontal and Uplift Bearing Characteristics of a Cast-In-Place Micropile Group Foundation in a Plateau Mountainous Area

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