Advanced Materials Research Vols. 671-674

Abstract: This paper analyzes the foundation excavation influence on construction foundations. The whole process of typical foundation excavation is simulated with the large-scale software-ABAQUS. The outer soil settlement is systematically analyzed. The incline value of masonry structure foundations is 0.00091m, which is less than 0.002m in the standard. It meets the requirements. So the deformational influence of the foundation pit on f construction foundations can be ignored.

Abstract: With the continuous development of urban underground space, the environmental effects of foundation pit excavation have been paid extensive close attention. Unfortunately, there are few researches in mucky soil and peaty soil. Adopted the software of FLAC-3D, the ground deformation due to the foundation pit excavation is simulated. Considering the characteristic of the soil, the Modified Cam-clay model and Mohr-coulomb model are used during the simulation. Meanwhile, the structure units are used to simulate foundation pit structure. The results of the field measurement and numerical simulation suggest that the influenced range soil is about 2.7 times of the excavation depth. Furthermore, the Modified Cam-clay model can obtain a better result to simulate the mucky soil and peaty soil in Kunming. The results can be referred to design and construct of foundation pits.

Abstract: This paper introduces the measurement principles and techniques of foundation pit’s pile body horizontal displacement. It is based on Dalian Maritime University station’s(Dalian Metro) construction. Then 26 monitoring measuring stations were built around the foundation pit. After 10 months’ measuring the data shows pile body horizontal displacement’s rule during foundation pit dewatering, excavation, support installing and the main structure of the construction. The maximum horizontal displacement conform the relevant requirement. In other words, it ensures the safety of the construction. At the same time, it points out that the pile horizontal displacement monitoring is key index of the information technology construction. Especially during the excavation of foundation, the pile horizontal displacement account for about 60%-80% of all. Steel support plays a significant role in horizontal displacement of the pit wall.

Abstract: Tianjin Binhai has the properties of poor geological conditions and much weak soil. Cement mixing pile is used to the bridges and the roadbed of channel and culverts in Tianjin Avenue projection. But there are some problems about the effective length. The cement mixing pile is considered to be pure friction pile when the length is shorter than the effective length. According to the displacement coordination condition of the top surface of the pile-soil under rigid foundation, the computing method of effective length for composite foundation is derived from the settlement.

Abstract: High-pile wharf is the most frequently used wharf structure form on soil foundation. However, few researches have been conducted to establish field overall evaluation methods capable of determining the berthing capacity of high-pile wharfs. Based on finite element numerical simulation, the stress-deformation relation, and the equations for loading-deflection relation at the pile head are obtained. The method to test the actual berthing capacity for real ship impact on high-pile wharf，as a direct and effective test method，and the security evaluation of high-pile wharf is put forward. These results can be used for reference to test the actual berthing capacity and to evaluate the security of high-pile wharfs.

Abstract: Hydrodynamic dispersion experiment was done with unsaturated silt loam. Depend on mass conservation law, the formulas to calculate coefficient of hydrodynamic dispersion was developed. According to the data of soil water and salt regime measured from the upright soil column, the coefficient of hydrodynamic dispersion was calculated, and the relation between hydrodynamic dispersion and average flow velocity in soil voids was built up. This approach has clear concept of physics, and the formulas are simple and applied.

Abstract: Arch dam’s failure is a super nonlinear irreversible process. The research on process of it would give quite important information for safety evaluation. In this paper, it analyses overload of the highest RCC arch dam of the world by strength reverse method and shows the process of dam’s failure from normal operation, local deformation to overall failure

Abstract: Earthquake or rainfall can arouse landslide, which will cause debris flow. Free surface water waves generated by plunging of debris flow cause devastating damage on human life. In this study, a numerical scheme for debris flow and free surface water wave was developed based on shallow water approximation, in which the interaction between these two flows was included newly. Generation of waves by plunging of debris flow is highly non-linear phenomena. Original CIP method and first order up-wind scheme mixed with second order central derivative scheme were adopted to simulate collision of two initially separated fluids (debris flow and still water). Six cases have been adopted to simulate the generation, propagation and run-up of water waves generated by debris flow. The time series of these two flows for these six calculating cases show the interaction of these two flows. Numerical results for interaction of debris flow and generated water wave are quite satisfactory and reasonable.

Abstract: Based on the one-dimensional wave theory, nondestructive testing with stress wave reflection method bolts is a kind of quick and effective detection method; the method was used to estimates the anchorage quality according to some parameters such as waveform, phase, amplitude, frequency as well as arrival time of both the incident wave and the reflected wave; stress wave velocity is the basic parameter for quality assessment, the velocity is depended on signal identification of the integrity bolts, especially the reflected ones from the bottom. This paper, through the transient dynamic response experiment of anchor in different anchor medium, analyzes the dynamic measurement signal waveform characteristics. The results show that, fixed end reflection signal is very strong , but bottom end reflection signal is very weak, even it is difficult to identify; the compactness of surrounding rock and anchorage medium have certain effect in dynamic measuring signal waveform characteristics, if surrounding rock and anchorage medium is uniform and dense, the wave type of anchor dynamic measuring signal is regular and steady, instead, signal clutter and irregular; model size and boundary conditions also have certain effect on the change characteristics of the signal, so this effect should be considered in laboratory experiment.

Abstract: The mega steel frame and cable bracing structure belongs to the pre-stressed high-rising building and how to estimate cross-sectional area of cables is one of key problems for this new structural system. Considering shear and bending deformation, the relationship between structural story drift and cross-sectional area of cables is established by using the superposition principle of deformation. Further, cross-sectional area of cables is determined based on the design target value of story drift that is known. The qualitative estimation method on cross-sectional area of cables is finally developed. The cross-sectional area obtained by using this method is its lower critical value, and the method presented is useful for the preliminary design and qualitative evaluation.