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For the design of rubble mound breakwaters on soft soil, it is essential to predict the behavior of soft soil and large deformations phenomena occurring in the course of construction of the rubble mound breakwater. Large deformations in various problems can be well simulated using the coupled Eulerian–Lagrangian (CEL) method. In this study, the CEL method has been used to simulate the rubble mounds construction on soft soil and predict the resulting settlements. To validate the numerical model, the results of three experiments conducted in the physical modeling laboratory at Kharazmi University were used. Also, two case studies of real rubble mound breakwaters constructed on soft seabeds were numerically simulated and the results of the numerical model were compared with the recorded data. According to the obtained results, the finite element analysis by the CEL method is able to predict the deformations and settlement occurred during construction of rubble mound breakwaters on soft soils with a reasonable accuracy. In very soft soils with undrained shear strength less than 10 kPa, the CEL simulation outperformed the Lagrangian formulation. Then, parametric study was performed and the effects of height, crest width, breakwater slope and thickness and strength of the soft soil on the amount of rubble mound settlement were investigated.

The construction of rubble-mound breakwaters on soft sea beds is problematic, but is necessary in many coastal areas. The issues faced include the penetration of the rock particles into the very so...

Assessment of liquefiable soils strength is a challenging task in engineering practice especially when a structure is founded on top of the liquefied soil. While it has been addressed and studied i...

Purpose The purpose of this paper is to study the distribution of active earth pressure in retaining walls with narrow cohesion less backfill considering arching effects. Design/methodology/approach To this end, the approach of principal stresses rotation was used to consider the arching effects. Findings According to the presented formulation, the active soil pressure distribution is nonlinear with zero value at the wall base. The proposed formulation implies that by increasing the frictional forces at both sides of the backfill, the arching effect is increased and so, the lateral earth pressure on the retaining wall is decreased. Also, by narrowing the backfill space, the lateral earth pressure is extremely decreased. Originality/value A comprehensive analytical solution for the active earth pressure of narrow backfills is presented, such that the effects of the surcharge and the characteristics of the stable back surface are considered. The magnitude and height of the application of lateral active force are also derived.

PurposeThe purpose of this study is to present a diagram for the lateral earth pressure of c–φ soils exerted on anchored walls in presence of surcharge.Design/methodology/approachTo this end, two-dimensional plane strain modeling of anchored wall was carried out in Plaxis software. To validate the numerical model, two excavations with different specifications were simulated and the model results were compared with the available results. Subsequently, a parametric analysis was done and based on its results, a diagram was proposed for the lateral earth pressure of c–φ soils including the surcharge effects.FindingsThe proposed diagram without the surcharge and cohesion effects is a trapezoidal with zero value at the ground surface that is linearly approaching the apparent earth pressure of sand according to Terzaghi and Peck (1967) at 0.1H (H: wall height). The surcharge and cohesion effects at the ground level is 4 Ka*q and 0, respectively, and below 0.1H, they are treated as the same way for lateral earth pressure of a retaining wall. It should be emphasized that the apparent pressure diagram for design does not resemble the real distribution of earth pressure against the wall and it is for calculating the values of the anchors loads.Originality/valueThe available diagrams to determine the earth pressure exerted on the anchored walls are related to sandy or clayey soils and do not take the presence of surcharge into account. Thus, the proposed diagram is quite original and different from the previous ones.

In many cases, the construction of rubble mound structures such as breakwaters over soft beds is inevitable in coastal areas. The common problems arising from these structures include sinking of the rubble into the seabed, shear failure, general seabed instability, severe settlement, and soft material flow into the rock pores. The present study investigated the use of sand mattress and geotextile as separation layers through physical-model testing. The results of the model without a separation layer showed that the individual penetration of aggregates into the soft bed and flow of soft clay into the rubble mound pores is the effective mechanisms in wasting rock materials. The results are suggestive of the 25% share of penetration in total material loss. Further, mud flow accounted for a 49% share compared to foundation settlement. It was shown that placing a separation layer under the rubble mound can help significantly reduce material loss and offers control over deformations. Using a sand mattress or a geotextile layer enabled a considerable reduction in material loss—26 and 39%, respectively—by controlling penetration and mud flow. The better performance of geotextile over the sand mattress can be attributed to its capacity for withstanding tension and its reinforcing role, helping reduce lateral deformations.

The current study was undertaken to study the effect of soil arching on active earth pressure distribution in retaining walls with c–φ backfill. An analytical approach is presented to develop a gen...

An anchored soldier pile wall is used for deep excavation stabilisation in the vicinity of buildings which are sensitive to displacement. In the current study, a three-dimensional model of anchored soldier pile wall was created in Abaqus software to estimate displacement and internal forces, especially due to surcharge. The effects of soil type, wall height, spacing of anchors and soldier pile rigidity were analysed. The results indicate that the surcharge had great effect on the wall deformation and the bending moment of the soldier piles; however, the bending moment of the lagging was less influenced by the surcharge.

In performance-based geotechnical earthquake engineering, the required degree and spatial extent of ground densification for mitigation of liquefaction beneath a structure should be determined based on the acceptable levels of performance of foundation. Currently, there is no solution for evaluation of the amount of settlement and tilt of footings constructed on a densified ground which is surrounded by a liquefiable soil. This implies the need for numerical procedures for simulation of seismic behavior of shallow foundations supported on both liquefiable and densified subsoil. In this paper, the dynamic response of shallow foundations on a densified ground is studied using a 3D fully coupled dynamic analysis. For verification of the numerical model, simulation of a series of centrifuge experiments has been carried out and the results were compared with the experimental measurements. After verification of the numerical model, a comprehensive parametric study has been performed to develop a methodology for estimating the effectiveness of subsoil densification in reducing liquefaction-induced settlement of shallow foundations. Range of problem variables were considered in a way that the possibility of bearing capacity failure is low enough. The proposed methodology can be utilized for development of a performance-based design procedure for liquefaction hazard mitigation by soil densification.