Papers by Keyword: Dynamic Compaction

Abstract: Earth construction is a sustainable and environmentally friendly approach to building. In addition to their good thermal performance, earth materials are abundant, inexpensive, and readily available, reducing the need for resource-intensive materials like concrete and steel. Regarding the construction process of earth structures, which is based on compaction, there is often a difference between the laboratory compaction process and the onsite one. The energy consumed onsite to produce earth structures is still approximative and uncontrolled, which affects considerably the mechanical performances of earth walls. Then, the investigation of the optimal compaction energy is necessary. To optimize the on-site compaction energy used in rammed earth (RE), an experimental study is carried out to compare the dynamic compaction usually applied to produce RE walls to the static compaction using a mechanical press. By considering increasing dynamic and static energies, the physical and mechanical properties are analyzed for each case. The obtained results show that RE walls can be replaced by prefabricated pressed earth blocks where the compaction energy is reduced by 60% and the compressive strength is enhanced by 70% using static compaction, thus achieving 4 MPa without stabilization. This solution allows to reduce the execution time and to control the quality of earth buildings.

Abstract: This paper deals with the large deformation analysis of partially saturated soils subjected to dynamic loading. The so-called ‘mixture’ theory is employed to consider the hydro-mechanical coupling involved in this kind of problem. The finite element method is used to discretise the problem domain and the generalized-α algorithm is employed to integrate the governing equations over time. Some of the most challenging aspects of dynamic analysis of partially saturated soils will be discussed. One of the key challenges is selecting a consistent constitutive model within the theory of mixtures that can incorporate the pore suction forces into the description of stress. The necessity of such incorporation has frequently been reported in experimental studies of unsaturated soils. To tackle this problem, a unique strategy for integrating the constitutive model for unsaturated soils is adopted. Moreover, an absorbing boundary condition, which prevents wave reflection from rigid boundaries, is introduced and implemented into the numerical algorithm. Finally, a solution for the problem of dynamic compaction of soil in a partially saturated condition is presented.

Abstract: The paper presents the dynamic response in motion and stress transmitted to the soil to rotating inertial dynamic excitations, for each layer of soil with specific stiffness. Upon repeated passages on the same layer of soil, there will be taken into account the new rigidities that change the dynamic response called "successive transition" within the linear - elastic limit, up to the ultimate the achievement of the last end state of deformability.Parametric variation curves are specific to certain regularities families expressing multiple correlations, useful for assessing the degree of compaction by vibration of natural soils, by highlighting the movement of resonance points after each pass on the same layer of soil.

Abstract: Survey data show the problem of weak foundation existing in an accommodation highway. There are many methods to treat the soft foundation, and different methods have different expenses, effects and construction periods. Through the deep comparison of four foundation treatment programs, dynamic compaction method is taken for the design, and the detection result shows that the treatment effect reaches the engineering requirements.

Abstract: Dynamic compaction is one of the densification techniques of ground improvement and extensive theoretical, experimental and in-situ tests have been used to clarify its mechanism. In this paper, a literature review about the dynamic compaction is carried out and the emphasis is put on the reinforcement mechanism, effective reinforcement depth and influence range of vibration to give a reference for the ongoing researches of dynamic compaction method.

Abstract: Direct shear tests by laboratory to study the red sandstone aggregate mixture under the action of water intensity decay law, got red sandstone aggregate mixture, fill high subgrade compaction experimental study, tests showed that dynamic compaction compacted earth and rock mix fill embankment feasible, Rayleigh Wave test results show that the effect of dynamic compaction compaction good.

Abstract: The experiment on foundation improvement by dynamic compaction in Collapsible Loess foundation of the power plant was made. Before and after the experiment, kinds of in-situ and laboratory tests were performed .Through these tests, the influence of the dynamic compaction on the character of the soil, such as dry density, collapsibility, bearing capacity is analyzed. The effective depth of improvement of foundation is calculated and the conclusion of the efficiency of the foundation treatment by dynamic compaction is made. The choosing of techniques and parameter of the dynamic compaction also is elaborated in the paper, which make an example for other similar construction in the future.

Abstract: Along with large national investment in infrastructure construction, the mileage of the highway, which is one of the infrastructures, has increased year by year. There are many kinds of artificial filling foundation treatment methods for housing construction project in mountain highway facilities. This paper, combined with the engineering example, focuses on the dynamic compaction method and the replacement method.

Abstract: Dynamic compaction is a widely used foundation reinforcement technique. But the energy of the foundation spreading around in the earth by the form of wave will produces bigger effect of vibration on the surrounding environment. It brings a lot of adverse effects to nearby residents life, work, and even to the safety of the surrounding buildings. In actual engineering, we often determine the feasibility of the dynamic compaction construction scheme by the compaction test, which is time-consuming and laborious. Based on the monitoring of stadium area soil compaction in the new campus of Wuhan University of Technology, we use dynamic finite element software named LS-DYNA to simulate the dynamic compaction construction and establish a set to conform to the model parameters of the actual project. We can change the tamping compaction model according to the different adjusting scheme to guide the construction.

Abstract: The applicability of the plate body stabilization technology was determined basing on the different treatment methods on soft foundation in Caofeidian areas. It discussed the construction technology and the main points of construction furtherly on the plate body stabilization technology. The soft foundation bearing capacity reached 200kpa and the settlement amount was less than 16mm through static load test after dealing with the soft foundation. The results meet the specifications and project requirements.