Monitoring and Analysis of Dynamic Response for Open-Pit Mine with Inside Inclined Shafts under Train Loading

The stability of open-pit mining is a hot issue in geotechnical engineering. A mining railroad is in operation on the slope where the east exhaust inclined shaft and the east sand injection inclined shaft on the Laohutai Mine are located, and it was necessary to determine whether railroad vibration would have an impact on the safety of the inclined shafts. With this project as the background, the dynamic response of the slope with inside two inclined shafts was conducted under train loading. A three-dimensional numerical model by using PLAXIS 3D was established to analyze the stability of the slope. The results show that the dynamic reaction caused by the full-loaded train is significantly greater than the no-load train. The safety factor of the slope under the dynamic load is 1.201, and the maximum displacement of the slope which occurred in the gravel layer directly beneath the train track is about 5 mm. The acceleration responses of the two inclined shafts are almost consistent. The maximum horizontal and vertical acceleration occur at the epidote weak layer. The acceleration directly below the load increases significantly. Therefore, it can be considered that the slopes are stable under the action of train vibration, and the influence on the two inclined shafts is small and negligible.

Fatigue design in reinforced concrete bridges according to Brazilian code

There has been an increase in the flow of freight vehicles commuting on Brazilian highways. Then, special attention to the structural performance of bridges regarding the fatigue in beams is needed. Brazil has neither normative metrology to study real data flow of vehicles, nor specific fatigue load train models and coefficients to the analysis and design of road bridges. The same load train that is used for general dimensioning, TB 450, is used for the fatigue verification. Hence, this work aims to verify if the current TB 450 is representative of the freight heavy vehicles with 2 to 9 axles concerning the effects of fatigue in the longitudinal reinforcement of beams of theoretical reinforced concrete bridges with two, three, and five beams. This verification is performed analyzing the stress variations found in the longitudinal reinforcement of vehicles with 2 to 9 axles and the TB 450. Based on the results, the longitudinal steel reinforcement was more susceptible to fatigue's effects. Freight vehicles with 5, 6, 8 and 9 axles presented the most significant stress, therefore, they tend to cause more deleterious effects. Hence, the adoption of a Brazilian normative fatigue specific load train and coefficients is necessary to analyze pre-existing road bridges and design new ones most accurately.

Optimizing Power Consumption of Freight Railroad Bearings Using Laboratory Experimental Data

Based on projected freight truck fuel efficiency, freight railroad and equipment suppliers need to identify, evaluate and implement technologies and/or operating practices to maintain traditional railroad economic competitiveness. The railway industry uses systems that record the total energy efficiency of a train but not energy efficiency or consumption by components. Lowering the energy consumption of certain train components will result in an increase in its overall energy efficiency, which will yield cost benefits for all the stakeholders. One component of interest is the railroad bearing whose power consumption varies depending on several factors that include railcar load, train speed, condition of bearing whether it is healthy or defective, and type of defect. Being able to quantify the bearing power consumption, as a function of the variables mentioned earlier, would make it possible to obtain optimal operating condition ranges that minimize energy consumption and maximize train energy efficiency. Several theoretical studies were performed to estimate the power consumption within railroad bearings, but those studies lacked experimental validation. For almost a decade now, the University Transportation Center for Railway Safety (UTCRS) at the University of Texas Rio Grande Valley (UTRGV) has been collecting power consumption data for railroad bearings under various loads, speeds, ambient temperatures, and bearing condition. The objective of this ongoing study is to use the experimentally acquired power consumption to come up with a correlation that can be used to quantify the bearing power consumption as a function of load, speed, ambient temperature, and bearing condition. Once obtained, the model can then be used to determine optimal operating practices that maximize the railroad bearing energy efficiency. In addition, the developed model will provide insight into possible areas of improvement for the next generation of energy efficient railroad bearings. This paper will discuss ongoing work including experimental setup and findings of energy consumption of bearings as function of railcar load, train speed, condition of bearing whether it is healthy or defective, and type of defect. Findings of energy consumption are converted into approximations of diesel gallons to quantify the effect of nominal energy consumption of the bearings and show economic value and environmental impact.

Application of Micro-CT in the Examination of the Influence of Different Intensities of Exercise on the Injury of Junction of Bone and Tendon

The purpose of this study was to investigate the effect of different intensities of exercise on the injury of the junction of bone and tendon. In this study, the feasibility of Micro-CT technology to calculate the thickness of fibrous cartilage band was investigated experimentally. Adult female New Zealand white rabbits were selected as the study subjects and randomly selected into 4-week cyclic load group (n = 8) and 8-week cyclic load group (n = 8). Among them, left hind limb was used for experiment and right hind limb was used as blank control. The results showed that the tissue morphology of the bone tendon junction was changed in each load group, while the tendon cell density was significantly increased in the high-exercise load group, and there was no significant difference in the thickness of the fibrous cartilage band. Micro-CT calculation results of bone mass and trabecular bone showed no significant difference between the experimental group and the control group. Therefore, it can be concluded that the intervention of different strength load train and rest on the injury of the junction of the patella and tendon can change the fine structure of the bone, but not the tissue changes of the junction of bone and tendon, and the bone reconstruction and recovery ability is stronger than the junction of bone and tendon.

Proposed Track Classification for Egyptian Railway Lines

The present research paper aims to reclassify the Egyptian Railway Network taking into consideration the safety and economy factors as Egyptian Railway suffers from track maintenance shortage. Lines are classified into several groups depending on dynamic load parameters to facilitate economic studies and comparisons between the worldwide railways. Then, discussions of four Railway line classifications are studied as follows: Theoretical classification of line Sections according to ENR, Actual classification of line sections according to ENR, UIC line classification and proposed classification of line sections for ENR by following the mentioned techniques. Three objectives are studied to reclassify the Egyptian Railway tracks: determine the traffic loads for all line sections of ENR based on official train schedule for year 2019, the track classification should be continuously defined each year taking the load, train type and the running speed as the main three effective parameters. The present methodology deduce some conclusion and recommendations to ensure both track safety and economical operational

Revisiting the generalized scaling law for adhesion: role of compliance and extension to progressive failure

The generalized scaling law for adhesion is revisited, based on the classical fracture mechanics approach, leading to a revised scaling law that accounts for the role of load train compliance and extends to progressive failure modes.

Study on Active Recovery of Anaerobic Ammonia Oxidation and Start-Up of ASBR Reactor

In order to prevent the loss of microbes, added anaerobic ammonia oxidation to (ASBR) reactor plus membrane as the growth of anaerobic ammonia oxidation bacteria carrier. After 30d cultivate, the activity of anammox bacteria restore to the original level, and improve TN volume load train anammox bacteria. The whole process of NH4+-N and NO2--N removal rate has remained at more than 90%.After the activity recovery of anammox NH4+-N, NO2--N the ratio of consumption to the NO3--N generation finally tends to a certain value (1. 00b 1. 30 b 0. 25).In the process of cultivate, the sludge was gradually changed from black to red brown color .Results show that the ASBR is well suited for anammox enrichment culture of bacteria.