The localization damage and deformation characteristics of multiple rock in mined-out area under thick soil layer were investigated by acoustic emission （AE）-based physical similar simulation experiment and damage t...The localization damage and deformation characteristics of multiple rock in mined-out area under thick soil layer were investigated by acoustic emission （AE）-based physical similar simulation experiment and damage test combined with the AE theory on rock damage. During different mining courses, the degree of wall rock suffered from mining disturbed process in mined-out area was different, so did the AE density of initial damage and fracture. Some characteristic parameters, including large events, total events, and energy rate, presented fluctuations with temporal and spatial change and take on a certain extent statistic relation. Subsequently, the percent of damage degree was defined and divided into 4 stages, and the localization damage and deformation characteristics of surrounding rock in mined-out area and coal pillars were analyzed quantitatively.展开更多
The measurement of the middle-convex and varying ellipse profile of a pistonskirt is a key technology because of its complex profile and high precision. Generally, a piston ismeasured on special device after it is mac...The measurement of the middle-convex and varying ellipse profile of a pistonskirt is a key technology because of its complex profile and high precision. Generally, a piston ismeasured on special device after it is machined. High accuracy can be achieved through this off-linemeasurement, but the result diverges from the actual dimension. Therefore, a no-contact in-sitemeasurement system is proposed. A laser displacement meter is used to measure the profile of thepiston skirt. A computer connected to the meter is used to process the measured data. A regressionanalysis method is used to process the ellipse section data. The method of moving average is used toprocess the middle-convex curve data. By using the given system, high measurement accuracy can begained, and the production requirement is met.展开更多
Based on the idea of optimization design of pile type, the composite foundations, which include cememt-flyash-gaavel (for short CFG) long piles and cement-soil (for short CS) short piles, and CS piles with CFG core as...Based on the idea of optimization design of pile type, the composite foundations, which include cememt-flyash-gaavel (for short CFG) long piles and cement-soil (for short CS) short piles, and CS piles with CFG core as well, are formed. The method of the site dynamic characteristic tests of the composite foundations is discussed. The test results show that fireworks bomb may replace demolitions as the vibration resource. Vibration time is about 0.1 sec. Horizontal vibration major frequency is at 22.476 - 56.436 Hz, and vertical vibration major frequency is at 15.538 - 55.884 Hz. The pile arrangements of the composite foundation in the same site have more effect on the acceleration peak value. From the point of vibration, the anti-seismic effect of the CS piles with CFG core is better than others.展开更多
基金supported by the National Natural Science Foundation of China (No.10402033)
文摘The localization damage and deformation characteristics of multiple rock in mined-out area under thick soil layer were investigated by acoustic emission （AE）-based physical similar simulation experiment and damage test combined with the AE theory on rock damage. During different mining courses, the degree of wall rock suffered from mining disturbed process in mined-out area was different, so did the AE density of initial damage and fracture. Some characteristic parameters, including large events, total events, and energy rate, presented fluctuations with temporal and spatial change and take on a certain extent statistic relation. Subsequently, the percent of damage degree was defined and divided into 4 stages, and the localization damage and deformation characteristics of surrounding rock in mined-out area and coal pillars were analyzed quantitatively.
基金This project is supported by the Fifth China Technology Innovational Items (No.01-101-19-13).
文摘The measurement of the middle-convex and varying ellipse profile of a pistonskirt is a key technology because of its complex profile and high precision. Generally, a piston ismeasured on special device after it is machined. High accuracy can be achieved through this off-linemeasurement, but the result diverges from the actual dimension. Therefore, a no-contact in-sitemeasurement system is proposed. A laser displacement meter is used to measure the profile of thepiston skirt. A computer connected to the meter is used to process the measured data. A regressionanalysis method is used to process the ellipse section data. The method of moving average is used toprocess the middle-convex curve data. By using the given system, high measurement accuracy can begained, and the production requirement is met.
文摘Based on the idea of optimization design of pile type, the composite foundations, which include cememt-flyash-gaavel (for short CFG) long piles and cement-soil (for short CS) short piles, and CS piles with CFG core as well, are formed. The method of the site dynamic characteristic tests of the composite foundations is discussed. The test results show that fireworks bomb may replace demolitions as the vibration resource. Vibration time is about 0.1 sec. Horizontal vibration major frequency is at 22.476 - 56.436 Hz, and vertical vibration major frequency is at 15.538 - 55.884 Hz. The pile arrangements of the composite foundation in the same site have more effect on the acceleration peak value. From the point of vibration, the anti-seismic effect of the CS piles with CFG core is better than others.
