Advanced Materials Research Vols. 243-249

Abstract: The foundation soil of the buildings and structures is often in complex initial stress states. The dynamic torsional shear triaxial tests are carried out on undisturbed and remodeling loess under different complex initial stress states by using the remolded DTC-199 torsional cyclic load triaxial apparatus, and the effects of each complex initial stress state parameter on dynamic shear modulus of loess are discussed. Results show that, other conditions being the same, the influence of angles of initial principal stress α₀ on dynamic shear modulus G_d of loess show a trend of the bigger α₀ is, the smaller G_d is. The effect laws of efficient of initial intermediate principal stress b₀ on G_d of loess are not obvious. When the dynamic shear strain is larger, the bigger initial deviator stress ratio η₀ is, the smaller G_d of loess is. The influence of initial average principal stress p_m0 on loess is significant. The bigger p_m0 is, the bigger G_d of loess is. G_d of undisturbed loess is greater than that of remodeling loess under the complex initial stress states.

Abstract: Fractured rock mass endures tensile-shear and pressure-shear effects under horizontal seismic force. Based on rock fracture mechanics and the maximum circumferential stress theory, the extending condition (that is, the critical acceleration), the extending direction and the crack extension length under different direction of horizontal seismic force have been studied. The results are useful for judging the risk of dangerous rocks and providing a theoretical basis of pre-identification in the earthquake zone.

Abstract: The field monitoring of dangerous landslide is an important measure for guaranteeing its safety, especially when surrounded by large-scale construction. The landslide located nearby a reservoir in Shandong province. To guarantee construction safety, we adopted the automatic monitoring method for monitoring surface displacement and the internal soil pressure. The whole system uses solar power to provide energy and uses GPRS to transfer data. This system not only can provide reliable information for project construction, but also promote the application of environmentally friendly, low carbon in the monitoring field of civil engineering.

Abstract: Based on the geometric properties of a gravity retaining wall, an optimal design model is proposed, and then the best cross-section of the gravity retaining wall can be obtained by using ANSYS optimal techniques. An example is given to verify the effectiveness and superiority of the optimal design method based on ANSYS, and the results show that the optimum design is better than the original one. Further, the comparison between the sub-problem approximation optimal method and the first-order optimal method is performed, and our investigation proves that the first-order optimal method is more economical and reasonable.

Abstract: Discontinuities influenced the stability of jointed rock slopes are taken as the main subject of investigation, network simulation of discontinuities in the rock mass was produced by using Monte-Carlo method. The establishment of jointed element model to carry out that the network model of discontinuities was applied to the numerical one, which made it feasible to consider the influence of discontinuities in course of analyses of the finite element method when evaluating the stability of jointed rock slopes. Finally, the method was preliminarily applied with real project of artificial slope for BaiLong nuclear power plant, it is proved that it is feasible to expand for engineering applications.

Abstract: SFG model has some advantages that it is more flexible in modeling different types of unsaturated soils than most other models in the literature. However, there are some shortages in SFG model. Firstly, it did not take account the influence of degree of saturation on the deformation of soil. Additionally, the SWCC that was adopted in the SFG model is relatively simple and cannot reflect the relationship between the current void ratio and the degree of saturation. This paper firstly presents the modified model based on the SFG model. The modified model adds the degree of saturation into the volumetric model for unsaturated soils. In addition, it adopts a SWCC that can reflect the influence of current void ratio. The new yield surfaces are proposed. These new yield surfaces are not only the function of suction and mean net stress, but also the function of the current degree of saturation and void ratio of soil. The modified SFG model can model more types of the behaviors of unsaturated soils and is more reasonable than SFG model.

Abstract: During freezing sinking, the displacement and affecting factors of deep alluvium frozen soil wall was a technical problem which need to be resolved. Based on designing frozen soil wall in deep alluvium in thousand metre vertical wall, making use of mathematic simulation software of FLAC after selected ten samples from exceeding 400metres depth as calculation model, which the frozen clay creep parameters with finite transformation considered, the maximum radial displacement was obtained. The factors affecting it such as frozen soil thick, height of deep alluvium, segment height, exposure time and excavated radius were utilized. The mathematic formula was acquired with regression analysis through fifty datas, and detected with in-situ measurement data. The result of two types coincids, which indicates it can provide conducting in designing frozen soil wall under similar geoloical projects.

Abstract: This paper adopts the Finite-difference method to research the distribution of ground additional stress and distortion in differently isotropic and non-isotropic foundation conditions, and uses the Finite-difference method to compare with the Finite-element method and the three-dimensional settlement method used by the code. Through comparative analysis, the reliability and superiority of Finite-difference method used for calculating ground additional stress and settlement are justified.

Abstract: Based on the analysis of the experiment, a statistical damage model can be established according with Weibull distribution from the basic characteristics of rocks, the statistic theory of heterogeneity and the microscopic principles of damages, analyze the constitutive relationship of rocks through the stress-strain relationship, heterogeneity, and the element sizes. According to the analysis of rock strength and failure models in numerical simulation, it is acquired the influence of heterogeneity and element sizes on rock mechanics properties. The results of numerical simulation provide a new way for the study of the medium macro behavior on the deformations and fractures.

Abstract: This article will use the mutation theory with qualitative and quantitative analysis, and utilizes the membership function of fuzzy mathematics, then decomposes the slope stability assessment to multi-level objectives, and then carries on quantification recursion computation according to recursion formula. As a result, we can figure out the total mutation membership function value of the slope stability according to the different factors of the slope, finally we can carry on tne fuzzy comprehensive analysis and assessment about slope stability.