Li Y.,Beijing Jiaotong University |
Wang L.,Beijing Jiaotong University |
Ding G.,Beijing Institute of Geology |
Ge B.,Beijing Jiaotong University |
Li D.,Beijing Jiaotong University
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2012
Bridge-subgrade transition section is a weak link between roadbed and bridges or culverts in existing heavy haul railway. To detect and evaluate the roadbed bearing capacity is the key to ensure the smooth of railway and comfort of moving train. In this article, Number 170 Bridge's bridge-subgrade transition section of Shuo-Huang railway is detected by K 30 plate loading test, light dynamic penetration test and laboratory test. The results indicate that 1, Foundation coefficient K 30 can intuitively characterize the subgrade stiffness and bearing capacity. The reinforced roadbed's foundation coefficient K 30 has increased from 15% to 40% in different positions of bridge-subgrade transition section. 2, There is good correlation between foundation coefficient K 30 and Light Dynamic Penetration N 10. Compaction coefficient and foundation coefficient K 30 has no correlation. 3, The bridge-subgrade transition section detecting of existing heavy haul railway should do enough light dynamic penetration test, and complementary with foundation coefficient K 30 standard. It has important significance for improving the detection efficiency and reducing detection cost and the disturbance of detection to existing railway operation.
Yang J.,China University of Mining and Technology |
Shi H.,China University of Mining and Technology |
Qi G.,Beijing Institute of Geology
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2016
The geological and mechanical conditions of roadways become more complicated compared with those in the shallow part with the mining depth increasing. Consequently, the nonlinear mechanical phenomena especially the problem of floor heave in the roadway occur frequently. In order to explore the most effective type of cable fixed in floor, at first, the mechanism of floor heave controlled by the base-angle-bolt has been analyzed in two ways including cutting off plastic slip line effectively and decomposing pressure according to the mechanical analytical model of the bolt controlling roadway floor heave. Then six types of base-angel-bolt with different materials and specifications have been designed to carry out bending test. According to the optimized analysis of the results, the most appropriate type of I-3 has been determined and successfully applied in the engineering practice of Kongzhuang -785 mine in Datun. And the displacement monitoring curve has indicated that an obvious effectiveness has been obtained by applying the type of I-3 base-angle-bolt. © 2016, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.
Ding G.,Beijing Institute of Geology
Advanced Materials Research | Year: 2012
Three-dimensional finite element analysis should be used in stability analysis of slope because it can overcome the short advantages of two-dimensional finite element and can simulate the complex topographic and geological conditions. Based on the large-scale triaxial shear test, the modified Duncan-Chang model is established. Based on strength reduction elasto-plastic finite element, stability of high fill embankment was studied with three-dimensional finite element method considering the complex terrain conditions. Study results suggest that plastic strain and displacement mutant of slip surface node can be a sign of slope instability as a whole. At the same time calculation of three-dimensional finite element also does not converge. Therefore, it can be slope instability criterion calculate whether the finite element static analysis converges or not. On the other hand, stability safety factor of high fill embankment under three-dimensional conditions is larger than that of two-dimensional conditions, which shows that boundary conditions of high fill embankment enhance its stability.
Han M.-D.,Beijing University of Chemical Technology |
Han C.-Y.,Beijing University of Chemical Technology |
Zhang L.-D.,Beijing University of Chemical Technology |
Qi G.,Beijing Institute of Geology
Advanced Materials Research | Year: 2011
An Environmental friendly sand-fixing agent of water-borne polymer(graft copolymer of starch with acrylic acid and acrylamide)was synthesized. The influences of monomer dosage ratio, initiator dosage, the temperature and reaction time on the properties were discussed. The structure, thermal stability and morphology was characterized by IR spectra, TG-DTA and SEM, respectively. With the sand soil as research object, the tolerance of high temperature and compressive strength of the sand-fixing agent were studied preliminarily. The results show that when the mass ratio of acrylic acid to acrylamide is 15:10, the mass content of initiator is 4%, the reaction temperature is 50°C and time is 6h, the product has a good sand fixation performance for practical application. © (2011) Trans Tech Publications, Switzerland.
Liu S.,Chinese Research Institute of Highway |
Ding G.,Beijing Institute of Geology
Advances in Environmental Vibration - Proceedings of the 5th International Symposium on Environmental Vibration, ISEV 2011 | Year: 2011
For roadbed and the transition section easily lead to problems of high-speed railway, dynamic response tests of the high embankment, low embankments, cuttings, half cutting roadbed and filling and excavation of transition section between bridge and subgrade are earned out when high-speed train passes. Through analyzing large amounts of data, the conclusions are made that dynamic displacement changes of different forms of embankment are not obvious as the train speed, and acceleration increase significantly with the continuous improvement of train speed. Dynamic response of the cut is greater than that of the high embankment and half-filled and hah-dug embankment, and dynamic response of low embankment is the minimum. In addition, the dynamic response of filling transition section is significantly larger than the cut transition section. The main reason is that the construction quality of the filling transition section is difficult to guarantee test by ground penetrating radar. Moreover, it is also found that the dynamic response of transition section increases with the train speed improvement. And in a certain distance to the abutment which is 31m in this article, the dynamic response of the transition section decreases with the increase of the distance from bridge abutment.
Chen X.-L.,China Earthquake Administration |
Liu C.-G.,China Earthquake Networks Center |
Yu L.,China Earthquake Administration |
Lin C.-X.,Beijing Institute of Geology
Geomorphology | Year: 2014
The 2008 Wenchuan earthquake in China triggered approximately 200,000 landslides. This study examined a detailed landslide inventory for the event. Based on Newmark's method, the correlation between critical acceleration and landslide occurrence was analyzed for the Beichuan region in Sichuan Province, where various kinds of geohazards occurred due to the earthquake. The results indicate that critical acceleration is a good and reliable criterion to assess slope stability, and that slope gradient and material component are important factors influencing landslide occurrences. It was found that external forces behave differently in different directions. Critical acceleration in horizontal direction is more important for assessing the stability of steeper slopes. This knowledge will help in the understanding of the mechanism of earthquake-triggered landslides and facilitate the combined use of critical acceleration and landslide distribution maps for determining peak ground acceleration in a region without abundant seismic instrument records. © 2014 Elsevier B.V.
Chen X.L.,China Earthquake Administration |
Yu L.,China Earthquake Administration |
Wang M.M.,China Earthquake Administration |
Lin C.X.,Beijing Institute of Geology |
And 2 more authors.
Natural Hazards and Earth System Sciences | Year: 2014
Earthquake-triggered landslides have drawn much attention around the world because of the severe hazards they pose. The 20 April 2013Ms Combining double low line 7.0 Lushan Earthquake, which occurred in the Longmen Shan region in Sichuan province, China, triggered more than 1000 landslides throughout an area of about 2200 km2, and completely blocked many roads and exacerbated overall transportation problems in the mountainous terrain. Preliminary landslide inventory is complied immediately following the earthquake, mainly based on the high-resolution remote sensing images. At the same time, the distribution of these landslides is statistically investigated to determine how the occurrence of landslides correlates with distance from the earthquake epicenter, slope steepness, seismic intensity and rock type. Statistic analysis is conducted using landslide point density (LPD), which is defined as the number of landslides per square kilometer. It is found that LPD has a strong positive correlation with slope gradients and a negative-exponential decline with the distance from the epicenter. The higher LPD values occur in younger strata systems like Quaternary and Tertiary sediments in the study area. Spatially, the triggered landslides are controlled by the causative faults and mainly concentrated around the epicenter. All the landslides are located within the area with seismic intensity ≥ VII and in line with seismic intensity. Generally, LPD value decreases with increasing distance from the epicenter, and sometimes landslides are densely distributed along the roads in the mountainous region. Also, this study reveals that the empirical relationship between distance and seismic magnitude is more suitable for estimating the landslide concentration area during the Lushan earthquake compared to other methods. © 2014 Author(s).
Liu S.-C.,Chinese Research Institute of Highway |
Ding G.-L.,Beijing Institute of Geology |
Chen G.,Bridge Group Co.
Geotechnical Special Publication | Year: 2014
An experimental study on engineering characteristics of the thicker soft-soil composite foundation preloading was developed in the throat area of a high-speed railway station, which mainly includes variation of excess pore water pressure, settlement deformation, and pile-soil stress with time in different positions and depths. It can provide a theoretical basis for related engineering design and construction. Some consolidation characteristic laws of composite foundation were obtained: (1) Excess pore water pressure of composite foundation increases with the growth of load. After excess pore water pressure peak appears, it will disappear with time. The change of excess pore water pressure lags behind load. Excess pore water pressure obtained maximum value at the top of substratum, where additional stress is larger. With the growth of depth, excess pore water pressure decreases gradually in substratum; (2) Ground settlement and layered settlement have the same rule of 35 m pipe pile decreasing the settlement at the middle throat area of a railway station. The settlement obtained maximum value in the middle of the reinforced area with 25m CFG pile; (3) Pile stress, soil between piles stress, and pile-soil stress ratio have a decreasing trend from the center embankment to the edge. In the process of filling and preloading, stress transfers from soil to pile. Pile stress increases, and soil between piles stress gradually decreases. © 2014 ASCE.
Qi G.,Beijing Institute of Geology |
Li Z.-J.,Hebei United University |
Guo Z.-B.,China University of Mining and Technology
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2011
In order to solve the support difficulties of deep soft rock roadways in No.5 Coal Mine of Hebi Coal Industry Group, taking the extending pit bottom engineering of Horizon 3 in the mine as an example, we analyzed the geological conditions and characteristics of surrounding rock, and evaluated the deep engineering difficulties firstly, by means of the field geological investigation, laboratory test, theoretical analysis, numerical simulation and on-site monitoring. The type of the roadway surrounding rock is determined to be high stress-jointed-swelling soft rockmass, with IABIIABDIIIAE compound deformation mechanical mechanism, according to the theory of soft rockmass engineering mechanics. Then the corresponding control countermeasures were analyzed by theoretical analysis and numerical simulation. Finally, the specific coupling support modes and parameters, and the appropriate construction process were put forward. The field construction and monitoring results show that the coupling support design composed of bolt- shotcrete-mesh-cable, base angle grouting bolt, and flexible layer truss, can effectively control the large deformations of deep soft rock roadways in the mine and ensure the long-term stability and safety operation of the roadways.
Yang Z.,University of Science and Technology Beijing |
Yang Z.,Jinchuan Group Co. |
Zhai S.,Beijing Institute of Geology |
Gao Q.,University of Science and Technology Beijing |
Li M.,University of Science and Technology Beijing
Journal of Rock Mechanics and Geotechnical Engineering | Year: 2015
To improve mining production capacity, a stage subsequent filling mining (SSFM) method is employed for Sijiaying iron mine. The height of the stage stope is approximately 100m. As there are farmlands and villages on the surface of the mine, the surface deformation should be controlled when the ore is mined out for the purpose of stope stability and minimizing surface subsidence. In this paper, according to the site-specific geological conditions, the self-stability of the stage-filling body was analyzed, and the failure mechanism of backfilling body was defined. Thus the relationship between the exposed height of filling body and the required strength was obtained. Next, the stability of backfilling body and the characteristics of surface subsidence due to mining of-450m level were analyzed using physical modeling. Finally, a three-dimensional numerical model was established using FLAC3D, with which the surface subsidence and the stability of stope were achieved. The results show that the stope basically remains stable during the two-step recovery process. The maximum magnitude of the incline is 10.99mm/m, a little larger than the permissible value of 10mm/m, and the horizontal deformation is 5.9mm/m, approaching the critical value of 6.0mm/m, suggesting that the mine design is feasible for safety mining. © 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences.