Advanced Materials Research Vols. 671-674

Abstract: An improved grey system model GM(1,1) was proposed in this paper, considered that the large difference between predicted results and measured load-settlement relationship results of bored piles, in which the prediction results were given by the original theory. The complete and incomplete load-settlement curves from pile loading tests were fitted and predicated by the improved grey model. The results calculated with empirical equations or methods in technical code for building pile foundations were compared with those predicted with the improved grey model. Analysis of a case study showed that the results predicted by the improved grey theory model GM(1,1) had higher precision, which demostrated that this improved theory was of significance in engineering practice.

Abstract: In the collapsible loess of Midwest China, quicklime compaction pile composite foundation has been widely used in practical engineering. Firstly，the calculation method of quicklime compaction pile composite foundation is analyzed; then the influencing factors of bearing capacity for quicklime compaction pile composite foundation was researched on the basis of the character about soil compaction effect between piles with the quicklime expanding when absorbing water from the soil; lastly, the calculation method was used in practical engineering, the results can be used to reference in reliability design application of composite foundation.

Abstract: Two full-scale destructive load tests were conducted on test piles to capture the response of post-grouted and non-post grouted piles. The results show that the relationship between end resistance and displacement developed at the pile base follows a linear model for the piles without and with post-grouting craftwork. It is observed that the limiting total skin friction of pile after post-grouting craftwork is 1.067 times that of non-post grouted pile, whereas the ultimate tip resistance of post-grouted pile is about 1.113 times that of the pile without post-grouting craftwork. At the ultimate loading level, the pile compression has been found to be 45.7% to 50.3% of the pile head settlement. For the long post-grouted pile, the pile shaft compression should be taken into account and enhancement of the shaft strength can reduce the pile head settlement.

Abstract: Georadar has many advantages, including good accuracy, high detecting capabilities, and user friendly results (data collected is shown pictorially thus easy to read). In addition, it has capabilities to provide real time information in field. In the present paper, the authors investigated the application of georadar in non-destructive inspection of Karst Cave underneath independent foundation. The results obtained improve our understanding of geometry and provide a foundation for effectively control the design and construction processes.

Abstract: Chengdu - Mianyang – Leshan (C-M-L for short) high speed railway in Chengdu section is located in the ground of weathered Mud rock overlying deep Chengdu clay area. Based on Chengdu clay ground of in high-speed railway construction project of CML, this article introduced the Burgers model to establish the objective function to analysis rheological constitutive model. The visco-elastic parameters of Burgers model are determined by back analysis of field monitoring data. By the method of iterative back analysis by layer of visco-elastic parameters, based on measured result, predicted the late settlement, and comparison with the follow-up observations records to verify the Burgers model.

Abstract: According to the raw multi-source data, all strata should be standardized. With the aid of the cubic spline interpolation function, the virtual drilling could be created. With the help of Deluanay triangulation, every stratum is turned to triangular net, namely initial stratum surface. A top triangle of stratum is connected with a corresponding bottom triangle of stratum in the net. It makes a triangular prism unit. Finally, according to certain rules, numerous triangular prism units are assembled orderly to form a geologic body. The GTP model can realize 3D strata simulation and the purpose of true three-dimensional.

Abstract: In this paper, the coupled calculation of continuous and discrete method was adopted to simulate the vertical static load test of single pile. The numerical result shows that the socket provided by FLAC and PFC can transfer data and complete coupling calculation well, and the displacement and force on contact surface of pile and discrete media are continuous. The result is approximately conforming to the P-s curve from field test, which indicates that the coupled method can be applied to the soil-structure interaction analysis.

Abstract: In this paper, taking the Zhengding new district of Shijiazhuang city as an example, we put forward to take advantages of analytic hierarchy process and rough set theory and combine them with fuzzy comprehensive evaluation method to do the quantitative analysis of suitability of the engineering geology conditions of urban construction land .It can make the evaluation more objective. This paper divides study area into the most suitable,suitable,less suitable and unsuitable,and provides a strong scientific basis for the design and planning.

Abstract: To reveal the process of geomorphic evolution of debris flow on slope, the qualitative-semi-quantitative model experiment was built from experimental model, characteristics of soil and rainfall scheme. The results indicate that the essence of geomorphic evolution of debris flow on slope is the interaction of soil and water. And the change of geomorphology is reflected by the elevation of topsoil. In antecedent rainfall, the elevation of topsoil is in increasing trend generally except some parts. During short heavy rainfall, the soil creeps intensively, mixes with water and becomes fluidization gradually. The elevation of topsoil on the top is decreasing generally, while on the button, the elevation is increasing. Moreover, because water infiltrates into slope and interacts with soil needing a period of time, the change of geomorphology falls behind the rainfall process.