Zhao Lianheng

Influences of nonassociated flow rules on seismic bearing capacity factors of strip footing on soil slope by energy dissipation method

Seismic bearing capacity factors of a strip footing placed on soil slope were determined with both associated and nonassociated flow rules. Quasi-static representation of earthquake effects using a seismic coefficient concept was adopted for seismic bearing capacity calculations. A multi-wedge translational failure mechanism was used to obtain the seismic bearing capacity factors for different seismic coefficients and various inclined angles. Employing the associated flow rule, numerical results were compared with the published solutions. For bearing capacity factors related to cohesion and equivalent surcharge load, the maximum difference approximates 0.1%. However, the difference of bearing capacity factor related to unit weight is larger. With the two flow rules, the seismic bearing capacity factors were presented in the form of design charts for practical use. The results show that seismic bearing capacity factors related to the cohesion, the equivalent surcharge load and the unit weight increase greatly as the dilatancy angle increases, and that the nonassociated flow rule has important influences on the seismic bearing capacity.

Experimental investigation on the resilient response of unbound graded aggregate materials by using large-scale dynamic triaxial tests

Resilient modulus is an important response index for unbound graded aggregate materials (UGAM) as a drainage layer in pavement structure. In this paper, a large-scale dynamic triaxial test (300 mm in diameter and 600 mm in height) is conducted with four gradations under conditions of repeated loading tests to investigate the resilient responses with various stress levels and water contents. Then, a model is introduced to quantify the moisture sensitivity of the resilient response of UGAM with the consideration of stress level, fine fraction porosity and gradation. Through comparison between experimental and predicted values, the proposed model is validated and shows that the resilient modulus at certain water content level can be predicted well when the resilient modulus at other water content level is known by experiment.

Limit-Equilibrium Method for Reinforced Slope Stability and Optimum Design of Antislide Micropile Parameters

AbstractAntislide micropiles can effectively reinforce slopes and improve their stability. To introduce the mechanical mechanisms of micropiles in slope stability analysis, this work adopted a reasonable failure mode for the micropile and simplified the interaction model into three parts: the geotechnical body around the embedded section of the antislide micropile, the sliding body, and the antislide micropile. This was done so that a simple calculation formula of the effective micropile side pressure was derived. Then, based on the assumption of stresses on the slip surface, a new limit-equilibrium method (LEM) was established for analyzing the stability of slopes reinforced with antislide micropiles. Meanwhile, contour curve charts of the factor of safety (FOS) were drawn for slopes reinforced with single-row antislide micropiles. Comparing with the limit analysis method (LAM) and traditional LEM, the current method exhibits similar results, indicating its feasibility; it can also obtain strict FOS solu...