Advanced Materials Research Vols. 446-449

Abstract: In order to study the characteristic of the hydrophilic and softening rate on the sandstone , which is the east guard mine in SHUANG YASHAN, it is experimented by the Hg-injection, the relation curve of the capillary pressure in the Hg-injection and the mercury ejection, the reason of the curve un-reclosing is analyzed and the inner porosity microstructure on the sandstone core is interpreted. It can be noted that the reason of the curve lagging on mercury ejection ,one is that the pore throat radius varies in the porosity microstructure of the sandstone and the more delaying lag can accelerate the hydrophilic rate; the other reason is that half close pore in the porosity microstructure of the sandstone residual mercury trapping lagging, when the trapping lagging is more bigger , the wetting phase is unease to exhaust.

Abstract: As a kind of emerging energy with massive reserves, natural gas hydrates are becoming the hot spot of global research. The elastic properties of gas hydrate bearing sediments (HBS) are the fundamental parameters for gas hydrates exploration and resource evaluations. As the original coring in HBS is difficult and expensive, experimental method is important to study the problem. An acoustic wave in-situ measuring system for HBS was developed. Using the in-situ method, hydrate bearing rock samples of different hydrate saturation were synthesized, of which the supersonic wave measurement was carried out under different confining pressure. According to the elasticity theory, the dynamic elastic parameters were obtained using the measured ultrasonic wave velocity. The results show that compressional and shear waves increase with the confining pressure and hydrate saturation increasing, and so the dynamic elastic modulus is.

Abstract: By comprehensive consideration of soil conditions, geometric shape of deep foundation pit and many other kinds of factors, enclosure structure design needs to select optimal supporting and enclosure system with safety, economy and construction feasibility. On case study of enclosure structure selection about typical soft soil foundation, this paper researches effects of force- deformation of enclosure structure by brace layout, and of economy and construction feasibility. The research results may offer reference for similar projects.

Abstract: Characteristic site period is an important index in seismic zonantion and seismic resistance design. In seismic response spectrum theory, the characteristic design period is closely related with site characteristic site period which is comprehensively covering site parameters (site categories, site shear wave velocity, site thickness, etc.). Two models, i.e., single-layer model and double-layer model, are adopted and theoretical solutions are deduced by means of the amplification coefficient function. The natural site period are theoretically deduced and presented

Abstract: Fully grouted bolt has been in wide use as a kind of support in geotechnical engineering. But the design method and application for fully grouted bolt is limited due to the shortage of its anchorage mechanism and mechanical behavior at present. So in this thesis an in-depth exploration of anchorage mechanism and mechanical behavior of fully grouted bolt will be done starting from the study of mechanics mechanism of fully grouted bolt, the result will provide reference for the design and application of fully grouted bolt and this have value of theory and engineering.

Abstract: Stepped-load creep tests of undisturbed and remodeled specimens of reticulate red clay was performed in the present study. Test results and analyses of the results show that: (1) Both undisturbed and remodeled specimens showed significant creep deformation in primary loading, unloading and reloading stage, and the creep deformation of remodeled specimen is much bigger than that of undisturbed one in primary loading and reloading stage; (2) The effect of a previous loading stage on the deformation induced at a succeeding stage is significant in primary loading and reloading stage; (3) The amount of the creep deformation can be calculated accurately by an empirical formula.

Abstract: Back-propagation method (BP method) is the supervised learning algorithm that is the most widely and successfully used in feed forward network nowadays. This paper dealt with the penetration and blasting experimental data by BP Neural networks, including of the influence of the velocity and attack angles to damage of multilayer medium penetration and blasting. Through handling of the experimental data by the BP Network system, coupled effects of quantity of explosive and buried depth can be uncoupled. The curves of infundibular crater radius vs. quantity of explosive and infundibular crater depth vs. buried depth of explosive was given. Base on computing results, it is shown that the neural networks method can be used to predict the damage of multilayer medium penetration and blasting.

Abstract: Iron hook is widely used to strengthen Chinese tenon-mortise joint to enhance its strength in southern China districts.To find strengthening effects of this material, by shaking table tests dynamic characters as well as seismic responses of a 1:8 scale wooden frame model were studied under conditions that each of its tenon-mortise joint was/was not strengthened by iron hook.By white noise excitation,values of basic frequency of both unstrengthened and iron hook strengthened models were obtained;by inputing El-centro earthquake waves of different peak acceleration values, displacement and acceleration responses of the models were obtained,dynamic magnification factors for tenon-mortise joints as well as models were discussed.Results show that after each tenon-mortise joint of the model is strengthened by iron hook,its basic frequency increases,its displacement and acceleration responses under earthquakes decrease.However as iron hook can only restrict tenon from pulling out of mortise but not rotation of the joint, the dynamic magnification factors for strengthened model still tend to increase under strong earthquake.Thus strengthening effects of this method are limited.

Abstract: Red Sea coral reefs in Saudi Arabia were dredged and reclaimed firstly, and then were treated by dynamic compaction as non-cohesive soil ground. Consolidated condition of improved ground within different depth is in different. Calculating settlements for different state ground should consider actual condition. Several semi-theoretical and semi-empirical settlement calculation methods mainly including Terzaghi’s method(1996), Teng’s method(1969), Meyerhof’s method（1956）are applied and analyzed to investigate the actual condition of improved ground according to the RSGT project test results, and the differences are proposed among these three methods.

Abstract: In order to predict tunnel surrounding rock pressure, this paper puts forward a series of dynamic numerical simulative model on the tunnel excavation. According to the change of rock damage in the construction program, it adjusts dynamically the mechanical material parameters of surrounding rock. So the model achieves the purpose which is controlling and simulating the process of tunnel progressive damage. In accordance with the numerical simulative results, it analyzes the relationship between the rock parameters with the plastic strain, radial displacement. Then this paper proposes a prediction method of tunnel surrounding rock pressure based on the theory of the progressive damage and method of characteristic curve. Finally, it compares the pressure on the numerical simulative models with on the site date, and it proves that the prediction method has practical engineering value.