scholarly journals Interaction peculiarities of a single unit bored pile with the surrounding rock mass under the horizontal load effect

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Ivan Khokhlov ◽  
Mikhail Zertsalov

Interaction peculiarities of a single unit bored pile with the surrounding rock mass under the horizontal load effect, as well as loss mechanism of piles bearing capacity, are considered. The article presents the numerical modeling results and a method developed on their basis for calculating piles in rocky soils under the horizontal load effect under the spatial elastic-plastic problem conditions, with the account of the contact behavior between the pile and the rock mass. The study of the single unit bored pile interaction and the surrounding rock mass under the horizontal and moment loads effect was carried out based on the numerical models’ analysis of the piles and the surrounding rock mass in a spatial setting using the finite element method. The use of regression analysis methods made it possible, to obtain parametric equations, based on the numerical modeling obtained results, that connected the studied response functions (bearing capacity and horizontal displacement of the pile) from preselected independent factors reflecting the geomechanical properties of the body and the design piles peculiarities. The developed calculation method allows at the preliminary design stage to estimate the horizontal pile displacement value, as well as its bearing capacity. Also, using the proposed technique, it is possible to make a piles load test schedule, which can be used in the field observation preparation at the design stage. The relevance of the topic is due to the fact that in modern construction practice, bored piles are used to transfer to the foundation significant loads, on the rock foundation from structures for various purposes, including transport (bridges and overpasses piers’ foundations, etc.).

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Jianxun Chen ◽  
Yanbin Luo ◽  
Yao Li ◽  
Lijun Chen ◽  
Chuanwu Wang ◽  
...  

In this paper, the field monitoring method is used to study the variation of rock mass pressure during the construction of a tunnel in phyllite stratum, and three functions are used to fit and analyze the variation of rock mass pressure with deformation, excavation time, and space. The results show the following (1) When the deformation increases significantly, the rock mass pressure decreases firstly and then increases. This is caused by the insufficient bearing capacity of the rock mass in the arch foot of the supporting structure after the excavation of the upper bench, which leads to a settlement of supporting structure and surrounding rock. (2) Compared with other kinds of fitting functions, the logistic function can better characterize the variation of the pressure of surrounding rock with deformation, excavation time, and distance from the face. This paper provides a reliable reference for the design and construction of the tunnel in phyllite stratum. The logistic function can be used to present and predict the change of rock mass pressure with deformation, excavation time, and space in similar rock mass conditions.


2014 ◽  
Vol 1065-1069 ◽  
pp. 491-494
Author(s):  
Hong Biao Liu ◽  
Qiang Zhang ◽  
Xian Peng Liu

The bearing capacity calculation in horizontal and safety assessment methods of high-pile pier slideway while large platform dragged horizontally to move to barge was studied based on the theoretic derivation and numerical simulation method. According to the research, the load effect of 6000ton slideway in the process of large platform dragged horizontally is obtained, the safety of slideway is evaluated, and the safety measures of slideway structure which should be taken during dragging platform are recommended. The results of the calculation and analysis show that the bearing capacity of slideway meet the requirements of design under the horizontal load of 11550kN by using uniform force to calculate, and the displacement is less than the width of the structure gap between two segments. The 6000ton sildeway is safe under horizontal load of 11550kN. These conclusions can provide the basis for the safety state analysis of high-pile pier slideway structure and the optimization of plan to move the large platform to load on barge.


2011 ◽  
Vol 243-249 ◽  
pp. 2095-2099
Author(s):  
Wei Guo Qiao ◽  
Yan Xin Lv ◽  
Lie Chang Wei

The auxiliary shaft ingate of Pengzhuang Coal Mine deformed greatly with large roof fallings. Through the analysis of destruction, the ingate reinforcement schema is put up according to the engineering consolidation experience and the advanced consolidation experience at home and abroad. On the completion of the ingate project, the surrounding rock mass is stable without apparent deformation. The two-side and roof deformations are 4mm and 5mm respectively according to the convergence deformation test, improving the integrity and bearing capacity of the shaft and pipelines effectively. Thus the deformation of the surrounding rock mass is under control, guaranteeing the long-term stability of the roadway.


Author(s):  
Van Min Nguyen ◽  
V. A. Eremenko ◽  
M. A. Sukhorukova ◽  
S. S. Shermatova

The article presents the studies into the secondary stress field formed in surrounding rock mass around underground excavations of different cross-sections and the variants of principal stresses at a mining depth greater than 1 km. The stress-strain analysis of surrounding rock mass around development headings was performed in Map3D environment. The obtained results of the quantitative analysis are currently used in adjustment of the model over the whole period of heading and support of operating mine openings. The estimates of the assumed parameters of excavations, as well as the calculations of micro-strains in surrounding rock mass by three scenarios are given. During heading in the test area in granite, dense fracturing and formation of tensile strain zone proceeds from the boundary of e ≥ 350me and is used to determine rough distances from the roof ( H roof) and sidewalls ( H side) of an underground excavation to the 3 boundary e = 350me (probable rock fracture zone). The modeling has determined the structure of secondary stress and strain fields in the conditions of heading operations at great depths.


Author(s):  
Ana Alencar ◽  
Rubén Galindo ◽  
Svetlana Melentijevic

AbstractThe presence of the groundwater level (GWL) at the rock mass may significantly affect the mechanical behavior, and consequently the bearing capacity. The water particularly modifies two aspects that influence the bearing capacity: the submerged unit weight and the overall geotechnical quality of the rock mass, because water circulation tends to clean and open the joints. This paper is a study of the influence groundwater level has on the ultimate bearing capacity of shallow foundations on the rock mass. The calculations were developed using the finite difference method. The numerical results included three possible locations of groundwater level: at the foundation level, at a depth equal to a quarter of the footing width from the foundation level, and inexistent location. The analysis was based on a sensitivity study with four parameters: foundation width, rock mass type (mi), uniaxial compressive strength, and geological strength index. Included in the analysis was the influence of the self-weight of the material on the bearing capacity and the critical depth where the GWL no longer affected the bearing capacity. Finally, a simple approximation of the solution estimated in this study is suggested for practical purposes.


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