Definition of Construction Parameters of Discrete Restraining Constructions

Purpose. There are many problems in the design of anti-landslide constructions, therefore discrete constructions are an alternative to solid anti-landslides. Despite the advantages of such constructions, difficulties also arise when using them. In this work, it is envisaged to develop methods for determining the zone of influence of discrete restraining constructions on the interaction of a sliding soil mass with them and a method for assessing the conditions of a stable state of the soil, which interacts with discrete restraining constructions, by constructing analytical dependencies necessary to determine the zone size and the soil stability coefficient. Methodology. Theoretical studies of geomechanical processes using analytical and numerical mathematical methods, as well as analysis and generalization of theoretical research results were used to achieve the purpose. Findings. The research results presented in the work allow, during the design of landslide discrete constructions, to determine the area of interaction of the shear with discrete retaining constructions, as well as to take into account the stability coefficient of the soil laid between the elements of the discrete retaining structure. Dependences were obtained for determining the zone size in which the sliding soil mass interacts, with discrete retaining constructions, and the soil stability coefficient in the zone of its interaction with these constructions. Originality. Analytical dependencies allow to calculate the boom of lifting the soil dumping arch between the elements of the discrete anti-landslide restraining construction and the coefficient of soil stability. Practical value. The research results allow, when designing discrete restraining constructions, to determine the area of interaction of the shear with these constructions and the stability coefficient of the soil laid between the elements of the discrete restraining construction.

Nonlinear response of laterally loaded rigid piles in sliding soil

This paper proposes a new, integrated two-layer model to capture nonlinear response of rotationally restrained laterally loaded rigid piles subjected to soil movement (sliding soil, or lateral spreading). First, typical pile response from model tests (using an inverse triangular loading profile) is presented, which includes profiles of ultimate on-pile force per unit length at typical sliding depths, and the evolution of pile deflection, rotation, and bending moment with soil movement. Second, a new model and closed-form expressions are developed for rotationally restrained passive piles in two-layer soil, subjected to various movement profiles. Third, the solutions are used to examine the impact of the rotational restraint on nonlinear response of bending moment, shear force, on-pile force per unit length, and pile deflection. Finally, they are compared with measured response of model piles in sliding soil, or subjected to lateral spreading, and that of an in situ test pile in moving soil. The study indicates the following: (i) nonlinear response of rigid passive piles is owing to elastic pile–soil interaction with a progressive increase in sliding depth, whether in sliding soil or subjected to lateral spreading; (ii) theoretical solutions for a uniform movement can be used to model other soil movement profiles upon using a modification factor in the movement and its depth; and (iii) a triangular and a uniform pressure profile on piles are theoretically deduced along lightly head-restrained, floating-base piles, and restrained-base piles, respectively, once subjected to lateral spreading. Nonlinear response of an in situ test pile in sliding soil and a model pile subjected to lateral spreading is elaborated to highlight the use and the advantages of the proposed solutions, along with the ranges of four design parameters deduced from 10 test piles.

Evaluation of Pile Application for Slopes on Bedrock Stability

This paper presents a numerical study that performs the stability of slopes on bedrock reinforced with single pile row at different locations. The slope is formed of top sliding soil layer that underlies over rock. The numerical analysis has been implemented by employing the three dimensional analysis using FLAC3D. The results indicate that as the pile location is moved towards the slope crest the displacement increases.In the single row of pile application, the factor of safety reached its maximum value when the pile located at the top middle of the slope. Considering the failure mode the results has conclude three failure modes; above, in front, and through the pile according to the location of the pile. Failure mode is also affected by socketed length of pile in bedrock layer. It is believed that the findings of this study contribute to the engineers performing slope stability analysis in practice.

Experimental Study on Direct Shear Creep Characteristics and Long-Term Strength of Red Layer Sliding Zone Soil in Southern Hunan

The creep characteristics of red layer sliding soil under the condition of different vertical loads and water contents were studied through a series of direct shear creep tests. Tests results showed that the water infiltrated to the sliding zone along the fissure of red layer sliding belt due to the crush of red layer sliding rock, leading to softening of sliding zone and acceleration of shear creep. When the shear stress reached the limit of long-term shear strength, sliding soil was broken suddenly with small vertical loads (50 kPa and 100kPa), while the sliding soil presented as a constant acceleration creep with enough vertical loads (200 kPa and 300 kPa). The inflection point in shear stress-shear displacement isochronous curve corresponded to the long-term strength of the soil.

Analysis of the Calculation Method of Active Earth Pressure of Unsaturated Expansive Soil

The properties of unsaturated expansive soil were analyzed, and the shortcomings of present methods which are explored to calculate the active earth pressure of unsaturated expansive soil on the retaining structure were discussed. Based on Coulomb’s earth pressure theory, a calculation formula of active earth pressure of unsaturated expansive soil was proposed taking into account of the swelling pressure parameters according to the condition of static equilibrium of sliding soil. The formula has simple composition and derivation process, is convenient for application, and the example shows that this method is reasonable.