Prediction Of Ground Deformation Research Articles

Research of Mining Subsided Land Reclamation System Based on GIS

Land reclamation is an effective measure in recovering land resources, protecting ecological environment and solving the contradiction between people and land. This paper adopts ArcEngine, ArcSDE, Oracle, Micirosoft Visual C# and other technologies to develop mining subsided land reclamation system which integrates reclamation suitability evaluation model, ground deformation prediction model, land cube calculation model and economic evaluation model. The system realized the information and network management about mining subsided land, provided the functions such as map operation, ground deformation analysis, earth volume calculation, reclamation suitability evaluation and economic evaluation. It can be used to help decision maker choose and plan their activities more effectively and scientifically to match situation of land reclamation and ecological restoration.

Predictions of ground deformations in shallow tunnels in clay 1 1Discussion by A. Verruijt (Delft University of Technology, Netherlands), C. Sagaseta (Universidad de Cantabria, Santander, Spain), and O.E. Strack (Sandia National Laboratories, Albuquerque, USA). Wei-I. Chou; Antonio Bobet, Tunnelling and Underground Space Technology , Vol. 17, pp 3–19

Predictions of ground deformations in shallow tunnels in clay 1 1Discussion by A. Verruijt (Delft University of Technology, Netherlands), C. Sagaseta (Universidad de Cantabria, Santander, Spain), and O.E. Strack (Sandia National Laboratories, Albuquerque, USA). Wei-I. Chou; Antonio Bobet, Tunnelling and Underground Space Technology , Vol. 17, pp 3–19

Response by the authors to A. Verruijt, C. Sagaseta, and O.E. Strack discussion to the paper: W. Chou and A. Bobet (2002). Predictions of ground deformations in shallow tunnels in clay, Tunnelling and Underground Space Technology, Vol. 17, pp. 3–19

Response by the authors to A. Verruijt, C. Sagaseta, and O.E. Strack discussion to the paper: W. Chou and A. Bobet (2002). Predictions of ground deformations in shallow tunnels in clay, Tunnelling and Underground Space Technology, Vol. 17, pp. 3–19

Application of the Elastic Boundary Induced by Shear History on Saturated Cohesive Soil

Induced anisotropy under three-dimensional stress conditions is one of the important factors in the accurate prediction of ground deformation and should be a primary consideration not only in the laboratory, but also in the field. To achieve this objective, torsional shear tests for saturated cohesive soils with induced anisotropy were performed. Induced anisotropy was generated by the shear history under constant p' (effective mean principal stress), α (direction of major principal stress) and b (intermediate principal stress coefficient) conditions in this study. The parameters α and b were also set up during the shear history process, and the drained torsional shear tests were carried out under constant p', α and b conditions using these specimens. The behaviour of soils during this process was examined in detail. The elastic boundary induced by the shear history was represented in three dimensional space. Furthermore, the uniqueness of this elastic boundary was examined by changing the stress level and the material of the specimen. In conclusion, the uniqueness of the elastic boundary induced by the pure shear history (constant p') on saturated cohesive soils was verified via these experimental results. The application of the elastic boundary in a wide range of stress level and material was thus shown.

Predictions of ground deformations in shallow tunnels in clay

Twenty-eight tunnels are used to evaluate predictions from an analytical solution for shallow tunnels in saturated ground. The solution assumes plane strain conditions at any cross-section perpendicular to the tunnel axis and poroelastic behavior of the ground and elastic behavior of the liner. Stresses and deformations are obtained with this method for short- and long-term conditions anywhere in the continuum. Of particular interest to this study are the short-term surface settlements at the ground surface. Comparisons between predictions and observations from actual tunnels show good agreement, generally within 15% difference. The analyses show that: (1) most of the ground movements are caused by the gap parameter, which is a measure of the three-dimensional deformations at the tunnel face, the physical gap between the liner and the perimeter of the excavation, and of the workmanship; (2) most of the ground deformations take place within a distance of three to four radii around the tunnel; (3) the bottom boundary of zero vertical deformation should be placed at a distance of two tunnel diameters below the tunnel center line, or at the location of a stiff soil layer, whichever comes first; (4) the horizontal movements around the tunnel are relatively smaller than the vertical movements; and (5) the analytical solution tends to underpredict the maximum soil deformations and overestimate the settlement trough; however, with an appropriate estimation of the gap parameter and small soil yield, the differences between predictions and observations are small.

Mechanical Properties of Saturated Cohesive Soil with Shear History Under Three Dimensional Stress Conditions

ABSTRACT There are many cases in which ground is subjected to stress history not only via artificial actions but also by tectonic movement. The effects of stress history under three dimensional stress conditions are one of the important phenomena which have to be evaluated for the accurate prediction of ground deformation. The purpose of this study is to supply the fundamental data relating to stress history which can be incorporated in prediction or design techniques. To achieve this objective, a series of hollow-cylindrical torsional shear tests was conducted on saturated cohesive specimens which were subjected to shear history under constant p', various directions and three dimensional stress conditions. From the experimental results, it was seen that the magnitude of the ultimate strength was the same for a given p' and not related to the shear history. On the other hand, the deformation characteristics (the elastic locus) behaved differently with respect to the shear history. The elastic locus developed by the stress history has directional and stress condition effects. Finally, taking into account the experimental results of the present study, the predominant parameters —the difference in the direction of shear, and the stress condition between the shear history and the shear— were selected. Using these parameters, the elastic boundary space due to the stress history was confirmed to evaluate the effects of the shear history under three dimensional stress conditions.

Prediction of Ground Deformation Due to Shield Excavation in Clayey Soils

ABSTRACT In recent years, because of the development of the technology in shield tunneling, deformation due to shield tunneling is mainly contributed by these occurring while a shield is passing and by subsequent deformations. Though a few methods have been proposed to predict the deformation in numerical, statistic and empirical ways, it is hard to say these methods can be used with confidence. Based on the accumulated measurement data of shield tunneling, it is known that the ground deformation when a shield is passing is mainly caused by the stress release at the cutting face and the tail. It is also known that the subsequent deformation is dependent on the maximum deformation that occurred during the shield passing and the liquidity index IL which is related to the sensitivity. The total deformation due to shield tunneling is divided into the two parts mentioned above. These are evaluated with the proposed prediction method in practical ways respectively based on accumulated measurement data.

Analytical Prediction for Tunneling-Induced Ground Movements in Clays

Current design practice to predict tunneling-induced ground movements is generally based on empirical methods that are subjected to some important limitations. For a ground deformation prediction d...