Papers by Keyword: Displacement Field

Abstract: According to the theoretical formula of compacting displacement field due to jacked pile in semi-infinite soil, calculation of displacement field produced during construction process of precast pile was carried out. And the changing trends of radial displacement with depth of pile penetrating, the maximum radial displacement with normalized distance r/D and vertical surface displacement with normalized distance r/D were analyzed in this paper. Then the Comparison between theory calculation results and the field test data was presented. The results show that the theoretical formula will fit with the actual situation of the site, when the soft soil properties around the pile are homogeneous and saturated. The further solving of compacting displacement field due to pile jacking was put forward.

Abstract: Multi-parameter description of crack behavior in quasi-brittle materials offers still enough space for investigations. Several studies have been carried out by the authors in this field [1-3]. One part of the publications by the authors (this work included) contain analyses of the accuracy, convergence and/or tuning of the over-deterministic method that enables determination of the coefficients of the higher-order terms in Williams expansion approximating the stress and displacement fields in a cracked body without any complicated FE formulations. These intermediate studies should bring together a list of recommendations how to use the ODM as effectively as possible and obtain reliable enough values of coefficients of the higher-order terms. Thus, the stress/displacement field can be determined precisely even in a larger distance from the crack tip, which is crucial for assessment of the fracture occurring in quasi-brittle materials.

Abstract: According to influence of pile groups of high-rise buildings on metro tunnels nearby, the research is made to analyze the stress of soil and the settlement of neighboring tunnels caused by pile groups. Based on the hypothesis of pile groups under flexible cushion cup, the plain strain of profile of tunnels is calculated by combining the load spreading property along over-length piles and Mindlin answer and the formula of displacement field of soil. In this way, MATLAB programs are made to get some useful conclusions by analyzing the influence factor of the settlements of tunnels such as the distance between them and the collocation of piles, the loading level and the scale of piles.

Abstract: The pile-bucket foundation is a new kind of foundation. In this paper, the ABAQUS software was used to analyze the soil displacement field and the soil stress field surrounding of the pile-bucket foundation under the multi-cycle horizontal loading. Under the horizontal load, the active area of soil separated from the basics; the passive region takes the shape of a parabolic ring of soil wedge rotate failure surface. The maximum displacement was in the direction of horizontal load line on the surface of soil near the bucket. Horizontal and vertical soil pressure changes are concentrated under the surface of the soil near the bucket, and the maximum horizontal soil stress was in the deep soil around the bucket. There is a point of inflection between 1/3 and 1/2 of the pile into soil , and the soil pressure that upper and lower the point increased in the opposite direction. The horizontal forced resistance of the foundation mainly distributed under the bucket and 1/2 of the pile into soil .The conclusion could provide a reference basis for the analysis of bearing mechanism and destruction characters of pile-bucket foundation

Abstract: Taken the excavation of TBM assembly underground chamber with deeply buried super large and complex section in Jinping Ⅱ Hydropower Station as the background, apply theoretical analysis and experimental method to study the rock deformation and displacement analysis. The result shows that, drilling and blasting method is used for construction which is divided into four layers from top to bottom according to the excavation, they are 8.5m, 5.5m, 6.0m,7.0m from top to bottom, respectively. the displacement of surrounding rock generally moves toward the direction of the free surface. The rock possesses spring back deformation pointing to internal underground chamber. The displacements of arch crown and floor are mainly vertical, and displacement of retaining wall is mainly horizontal. This is significantly different from the rock deformation of underground chamber under general stress after excavation. The chamber displacement distribution under high crustal stress is closely related to stress direction. Location axis of underground chamber should parallel the direction of maximum principal stress. Under the complex and great deeply buried condition, excavation of large section tunnel by digging from the top layer can better release the rock stress, and the rock displacement changes gently, which is conducive to rock mass stability and structure security.

Abstract: 3D thermal-mechanical coupled numerical simulation of heat pulp mould was carried out. The numerical simulation result shows the rising up process of mould temperature. Temperature distribution contours shows the temperature status on the mould. Temperature distribution results provide reliable guarantee to change the mould structure, so that the temperature distribution on surface becomes uniform. Displacement contours show the mould deformation under the coupled effect of hot temperature and mechanical pressure. The displacement value of nodes can offer reference size to scale mould at the design stage. As a result, high accuracy mould will be manufactured, and this will improve the passing rare of product.

Abstract: The movement and deformation of rock stratum occur when the excavation is carries out during the underground mining process. Rock is a continuous-discontinuous material so the continuum mechanics method may not handle the rock problem well. The discontinuous deformation analysis (DDA) method which discretizes the rock mass to block system can describe the large displacement and deformation of rock blocks, especially the rock stratum collapse. The DDA was employed in this paper to analysis a mining excavation process. The displacement field and stress field of rock stratum was computed. The result shows that the DDA can handle the mining excavation and the rock stratum movement and deformation problem well.

Abstract: Expansive soil is called as “problem soil”, which has a characteristic of swelling by absorbing water and shrinking by losing water. So buildings and sub-grade which are built on expansive soil, are easier to damage for lager deformation. Due to the large-scale urban construction, ground surface was covered in a wide range. For example, in tropics and subtropics areas, the water transfer in the expansive soil is influenced by the gradient of temperature, which is different between the central area under the road surface and road-side bare area. Because of the hysteresis of water transfer, the water content distributing is not uniform, which lead to the different swell-shrink performance in different zone, herewith will change some parameters of the expansive soil and finally affect its stress field and the displacement field. Take the road as the example: The road is a strip belt-shaped coverage. Both in dry and wet season, the thermodynamic field and water-flowing field is uneven between the central area under the road surface and road-side bare area, so the displacement field and the stress field on the cross-section under the road is uneven. Under the load of vehicle, the non-uniformity stress distributing in the soil is further aggravated, and the same to the displacement in the underlying sub-grade, which is a significant factor in aggravating the dehiscence of road surface. Comparing to general soil, expansive soil has a completely different distribution of temperate field and water-flowing condition because of its swell-shrink characteristic. By studying on the relationship between the thermodynamic field and the stress-strain in the expansive soil, it can find out how the climate affect the engineering expansive soil, and provide the theory basis for improving expansive soil.

Abstract: Through the coupling analysis of temperature and displacement fields in freeze-thaw process of soil by ABAQUS software, a numerical simulation method of the two fields coupling in freeze-thaw process of soil is put forward. In computation, the temperature field is analyzed firstly, and then the physico-mechanical parameters are defined as functions of temperature field. The geometric model and boundary conditions of numerical simulation are identical with these in laboratorial tests. By comparing the computation results of soil freeze-thaw process with its laboratorial test results, it was found that on the curve of soil freeze-thaw process obtained from laboratorial tests there is a short frost-swelling phenomenon at the initial stage of freeze-thaw process, and then is continuous thaw condition, but on the numerical computation curve, the reflect of soil frost swelling stage isn’t obvious. With the exception of this the numerical computation result and laboratorial test result are more identical. The frost-swelling quantum is very small, so the main expression of overall deformation of soil is thaw-settlement deformation. Therefore the frost swelling phenomenon doesn’t influence the end quantum of settlement. For this reason, the computing method introduced in this paper can be used to conduct numerical simulation of the thaw-settlement of frozen soil and to a certain extent guide the designs of subgrade and pavement in permafrost zones.

Abstract: Corrugated fiberboard is considered as the world’s environmentally acceptable packaging that has a wide range of applications in packaging field. Through studying the characteristics of elastic wave propagation in the Corrugated fiberboard, this paper inferences variations of displacement and stress with time, when the corrugated fiberboard suffering the uniform load. It provides theoretical and mathematical basis for the design of cushioning package.