Bearing capacity of strip footings on undrained slopes using finite element limit analysis(PDF)
长安大学学报(自然科学版)[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2019年03期
- Page:
- 45-52
- Research Field:
- 道路工程
- Publishing date:
Info
- Title:
- Bearing capacity of strip footings on undrained slopes using finite element limit analysis
- Author(s):
- ZHAO Minghua1; XU Jiazhun1; ZHANG Rui2; XIAO Yao1
- (1. Institute of Geotechnical Engineering, Hunan University, Changsha 410082, Hunan, China; 2. School of Civil Engineering, Central South University, Changsha 410075, Hunan, China)
- Keywords:
- road engineering; finite element; limit analysis; undrained slope; strip footing; ultimate bearing capacity
- PACS:
- -
- DOI:
- -
- Abstract:
- In order to calculate the bearing capacity of strip footings on undrained slopes, first, according to the bearing characteristics of strip footing on slopes, the footing was assumed to be a smooth rigid body and there was no friction between the base and the soil, the footing buried depth was replaced by overloads on both sides, the problem was considered to be a plane strain problem, and a calculation model was established. Second, the stress field and velocity field was discreted by finite element, and the constraint equations of nodal stress and nodal velocity was established, according to the upper and lower bound theorems. The total internal energy dissipation or external force load was used as the objective function, a mathematical programing model was established and an appropriate algorithm was used to solve the function,and the strict upper and lower solutions were obtained. The hyperbolic approximation of the MohrCoulomb criterion was processed during the optimization calculation. At the same time, the results of this paper were compared with the existing results, the correctness of the method was verified. Three types of failure mechanics were summarized, and the design tables for undrained slopes were presented to provide reference for engineering practice. Finally, based on the numerical results, the effects of slope height H, the distance between the foundation and the top of the slope L, overload q, slope angle β, and cohesion Cu on the bearing capacity factor p/γB were evaluated. Where γ was unit of weight, B was the width of slope top foundation, p was bearing capacity of foundation. The results show that p/γB increases with an increase in H sharply and eventally apparoches a constant, the critical slope height is two times that of the footing width. p/γB increases with an increase in L/B and eventally apparoches a constant. p/γB increases linearly with overload q and the larger the L/B, the faster is the growth rate. The relationship between p/γB and slope angle β is linear, and it decreases with an increase in the slope angle β. p/γB is linear with the cohesion Cu/γB, and it increases with the increase in cohesion Cu/γB. 1 tab, 13 figs, 23 refs.
Last Update: 2019-05-23