Indoor Simulation Test Research Articles

Atmospheric Corrosion Behavior and Mechanism of a Ni-Advanced Weathering Steel in Simulated Tropical Marine Environment

Corrosion behavior of Ni-advanced weathering steel, as well as carbon steel and conventional weathering steel, in a simulated tropical marine atmosphere was studied by field exposure and indoor simulation tests. Meanwhile, morphology and composition of corrosion products formed on the exposed steels were surveyed through scanning electron microscopy, energy-dispersive x-ray spectroscopy and x-ray diffraction. Results indicated that the additive Ni in weathering steel played an important role during the corrosion process, which took part in the formation of corrosion products, enriched in the inner rust layer and promoted the transformation from loose γ-FeOOH to dense α-FeOOH. As a result, the main aggressive ion, i.e., Cl−, was effectively separated in the outer rust layer which leads to the lowest corrosion rate among these tested steels. Thus, the resistance of Ni-advanced weathering steel to atmospheric corrosion was significantly improved in a simulated tropical marine environment.

Experimental investigations on seismic response of riser in touchdown zone

A series of indoor simulation tests on a large-sized shaking table was performed, which was used to simulate the earthquake ground motion for the pipe–soil interaction system to be tested. The purpose of this study is to examine the dynamic characteristic and seismic response of a length of PVC pipeline lay on a clay seabed under seismic load. The pipeline was fully instrumented to provide strain and acceleration responses in both transverse and in-line. Dynamical modal tests show that corresponding mode shapes vertically and horizontally are basically the same. But the absolute values of the natural frequencies vertically are all higher than those corresponding values in transverse. It turned out that the geometry configuration of riser affects its stiffness. Seismic response of pipeline depends significantly on the waveform, and Peak Ground Acceleration (PGA). As the seismic loading progressed, the strain response was severe around both TDZ and catenary zone. Additionally, strain responses in top and bottom positions were more severe than the result in left or right side of the pipeline in the same section.

Indoor simulation test of step vacuum preloading for high-clay content dredger fill

ABSTRACTVacuum preloading is a soft ground improvement method that has been successfully used by geotechnical engineers and specialists to accelerate the rate of consolidation. However, consolidation efficiency is low when dealing with newly reclaimed high-clay content dredger fills because of sludge plugging of the prefabricated vertical drains. In this study, step vacuum preloading was proposed to reinforce a high-clay content dredger fill by applying the vacuum load gradually to consolidate the dredger fill fully and to reduce the migration of fine particles. An indoor simulation test was conducted, and monitoring data were obtained. Results showed that the settlements increased gradually, the pore water pressures and flow velocities decreased over time, and all the changes tended to be stable by the end of the test. The settlements at each stage were more than that at the previous stage, illustrating that changing the method of drainage consolidation in a timely manner, or increasing the vacuum pressure, can more fully consolidate the dredger fill at each stage, thus improving the consolidation efficiency of the dredger fill. The reinforcement effect of the high-clay content dredger fill was also analyzed. The results show that the moisture contents and porosities decreased gradually, the bearing capacity increased gradually in the consolidation process, and each property index of the dredger fill changed with the increase in degree of consolidation, and the regularity of the distribution of the indices showed that obvious siltation did not occur in the consolidation process. Overall, the consolidation efficiency was effectively improved. Thus, the step vacuum preloading method is suitable for high-clay content dredger fills. This method can improve the consolidation efficiency and the uniform reinforcement effect.

Analysis of tag recognition ranges and rates according to reader transmission power levels when tracking machines by RFID in underground mines: an indoor experiment

The objective of this study is to use indoor tests to quantitatively analyze how Radio Frequency Identification (RFID) reader transmission power levels affect tag recognition range and rate when tracking machine locations using an RFID system in an underground mine. We installed an RFID reader and antennas in an indoor testing site that simulates an underground mine drift and operated unmanned autonomous cars with tags attached to them. The tag recognition range and rate were measured for various reader transmission power levels. The results show that the location tracking is more precise when the reader transmission power is reduced; however, tag recognition rates also decrease. Therefore, it is necessary to adjust the reader transmission power accordingly when using RFID to track machines in an actual underground mine. The indoor simulation test methods used in this research should be useful for this process.

Stability Analysis and Charts for Borrowed Soil in Ecological Slope Engineering

The mechanical stability of man-made mixed slurry sprayed on a sloped surface, i.e., borrowed soil, in ecological slope engineering is examined in this study. Through indoor simulation tests, the failure mode of the soil without seepage and with surface seepage is found to be a translational sliding surface parallel to the original sloped surface. An infinite slope case is assumed on the basis of the obtained failure mode, and stability analysis of the soil is performed. A general equation is then formulated for the instability thickness of the borrowed soil under the actions of earthquake loading and seepage. The stability charts for the borrowed soil are produced after the parameters of the equation are defined. The charts are basically the same in form as Taylor’s stability charts. The charts are proved valid by indoor simulation tests. With the charts, the instability thickness of the borrowed soil can be designed with a given design safety factor, and the safety factor of the borrowed soil in ecological slope engineering can be deduced.

Experiment of Driving Oil by Low Frequency Hydraulic Pulse of Low Permeability Reservoirs

The fine grain, poor sorting and high cement content in low permeability reservoirs lead to poor reservoir property, low porosity and permeability and have strong damage to the reservoir .The conventional way of low permeability oil mining is mainly fracture and chemical flooding, which cost is relatively high and will cause serious irreparable damage to formation. People are in favor of physical oil production technology because it is no harm and pollution to the reservoir, more flexible to operate and it has wide range of application and low cost. By using high frequency pulse pressure servo system and ZC-type I, this paper examines the low-frequency vibration oil recovery indoor simulation test device hydraulic pulse oil displacement effect of low permeability cores. The experiment selecting the artificial core (permeability are less than 50), examines the effects of different hydraulic pulse parameters (frequency, static pressure and dynamic pressure) on low permeability core permeability and recovery factor. The results showed that only when the three parameter ,hydraulic pulse frequency, static pressure and dynamic pressure, suitably combined will greatly increase the reservoir recovery efficiency and reduce residual oil saturation.

The Development and the Field Application of the On-Line Dry Ice Washing Vehicle System

Abstract: In order to wash the polluted substation insulator quickly and safely, so as to improve the reliability of substation systems, an on-line dry ice washing system which would be applied in 220 kV voltage level was developed. Based on the results of the indoor simulation tests which provided the optimal washing parameters, the on-line dry ice system was developed. Moreover, a trial test was run in a 220 kV substation belonging to Hubei State Grid. The test results show that the vehicle system can meet the requirements of on-line washing tasks in 220 kV substation. Therefore, the washing system features advanced technology, excellent performance, and promotional value.

Experimental Study on Hydrodynamic Pressure Generated by Sleeper Loose

Through indoor simulation test of double-block ballastless track sleeper loose hydrodynamic pressure, this paper study the variation laws of hydrodynamic pressure of different position, different load and frequency variation. The results show: The location of the biggest hydrodynamic pressure is in the middle of the crack and near the not void area. The amplitude and frequency of load have obvious influence on the hydrodynamic pressure. When the load amplitude is more than 30kN or load frequency exceeds 10HZ, the effect on the hydrodynamic pressure is particularly notable.

Experimental Research on Embankment Hidden Defects Monitoring Using Distributed Optical Fiber Sensor

Distributed optical fiber sensor for temperature and strain identification as the basis, the optical fiber sensor has advantages to monitor deformation and seepage in the embankment dam relying on its long distance and continuous monitoring ability. Taking layout of layered installation, the relationship between laying bending radius and the strain of the optical fiber sensor is studied. Indoor simulation test and local outdoor dam model test show that, the distributed optical fiber sensor for dam defect monitoring has good effect and application prospect. The embankment dam model provides experimental platform to further study early warning criterion of impending disaster in embankment dam.

Effect of Pretreatment of Traditional Chinese Medicine Residue on the Biogas Productivity

The object of this study is to open the new ways of exploitation and utilization of traditional Chinese medicine residue (TCMR) as new energy material to produce biogas through indoor simulation tests. The experiment is carried out to study the effect of physical pretreatment by crusher on the biogas productivity of TCMR under medium temperature condition (35°C). TCMR is used as signal fermentation material without foreign elements which is 5% and cow dung is 10% for inoculum. The batch anaerobic digestion technology and the drainage collection biogas method are used. The results show that there is similar total biogas yield between the smashed TCMR and the unsmashed TCMR, of which the former is 9.35 L and the later is 9.28 L during 51 days fermentation. The biogas yield of smashed TCMR is higher than that of TCMR during fermentation starting period, and lower at the later stage. The results suggest that TCMR could be regarded as biogas fermentation material, and should not be smashed in order to economize the production cost.