Study on borehole stability in fractured rock mass in deep ground using distinct element method

2014 ◽  
pp. 421-426
Author(s):  
A Taheri ◽  
S Akkari ◽  
R Frimpong ◽  
J Ji ◽  
S Piotrowski
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Distinct Element ◽  
Distinct Element Method ◽  
Fractured Rock Mass ◽  
Borehole Stability ◽  
Element Method

Research on Seepage Field in Fractured Rock Mass of Underground Oil Storage Cave Using Distinct Element Method

2013 ◽  
Vol 353-356 ◽  
pp. 619-623
Author(s):  
Song Yu ◽  
Yun Peng Zhang ◽  
Wei Shen Zhu
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Distinct Element ◽  
Water Pressure ◽  
Hydraulic Pressure ◽  
Fractured Rock Mass ◽  
Water Curtain ◽  
Oil Storage ◽  
Underground Caverns ◽  
Element Method

The distribution of hydraulic pressure in fractured rock mass surrounding caverns after excavation and technique of stochastic generation of joint network are investigated based on discrete element method. In order to seal the oil in underground caverns with water in the actual engineering, a water curtain with water pressure is installed, and the changes of hydraulic pressure are simulated with a series of curtain pressures. It is shown that some joints that have been drained out during excavation can not be saturated if the water curtain pressure is less than a certain value. Water curtain pressure with a certain value gives a strong safe guarantee of saving oil in the underground petroleum storage caverns.

Study on Seepage Field of Artificial Water Curtains for Underground Petroleum Storage Caverns in Fractured Rock Mass

2013 ◽  
Vol 353-356 ◽  
pp. 1666-1670
Author(s):  
Yun Peng Zhang ◽  
Song Yu ◽  
Wei Shen Zhu
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Distinct Element ◽  
Water Pressure ◽  
Underground Water ◽  
Calculation Model ◽  
Fractured Rock Mass ◽  
Water Curtain ◽  
Underground Caverns ◽  
Water Seal

Based on joint statistics from the in-situ survey, using numerical simulation technique of joint network (Monte-Carlo method), the calculation model of fractured rock mass is generated. Underground seepage discharge filed in fractured rock mass surrounding storage caverns is analyzed by using distinct element method. The result of simulation has shown good agreement with surveying data. Two cases have been simulated that is water curtains is installed and is not installed. Water pressure distributions in joints are investigated in these two cases. It is shown that in the case without water curtain the groundwater in joints which locate the upper of underground caverns is drained out and water sealed conditions is completely unrealized. When water curtain pressure is set at 0.3MPa, can underground water seal the storage caverns.

scholarly journals Evaluation of seismic effects on the landslide deposits of Monte Salta (Eastern Italian Alps) using distinct element method

2007 ◽  
Vol 7 (6) ◽  
pp. 695-701 ◽  
Author(s):  
G. Marcato ◽  
K. Fujisawa ◽  
M. Mantovani ◽  
A. Pasuto ◽  
S. Silvano ◽  
...  
Keyword(s):  
Seismic Waves ◽  
Fractured Rock ◽  
Distinct Element ◽  
Vertical Component ◽  
Distinct Element Method ◽  
Cretaceous Rock ◽  
First Case ◽  
Civil Defence ◽  
Landslide Deposit ◽  
Element Method

Abstract. The aim of the paper is to present the modelling of the ground effects of seismic waves on a large debris deposit lying on a steep mountain slope, with particular attention paid to the potential triggering of slope movements. The study site is a mass of 2.5 million m3 rock fall deposit, named "Monte Salta Landslide", located on the northern slope of the Vajont valley, at the border between Veneto and Friuli Venezia Giulia regions in north-eastern Italy. Several historical landslide events were reported in the area in the past, first one dating back to the 17th century. The landslide deposit completely mantles the slope with a thick cover of rock blocks. The Mt. Salta landslide is conditioned by the presence of Mt. Borgà regional thrust, which uplifts Jurassic limestone on the top of Cretaceous rock units. Above the thrust zone, folded and highly fractured rock mass dips steeply towards the slope free face, producing highly unstable setting. The study area has been classified as high seismic hazard and different vulnerable elements can be affected by the remobilisation of debris, among which a village, a national road and a big quarry that was opened, with the intent to exploit the part of the landslide deposit for construction purposes. In this study, numerical analysis was performed, to simulate the slope behaviour using distinct element method and applying UDEC code. The 2-D models were built on three cross-sections and elasto-plastic behaviour was assumed, both for rock matrix and discontinuities. The earthquake effect was modelled in pseudo-dynamic way, i.e. by magnifying the acceleration and applying also its horizontal component. The expected seismic acceleration in the study area was calculated on the basis of previous studies as equal to 0.28 g. The results proved that the increase of the vertical component alone has a small influence on the deformational behaviour of the system. Hence, the acceleration vector was deviated at 5° and then at 10° from the vertical. A small increment of the displacement was observed in the first case, whereas very large movements occurred in the second. Therefore, it can be concluded that, besides the magnitude of the earthquake, even small seismic waves in horizontal direction could trigger significant movements and therefore hazardous conditions. The modelled scenario should be helpful for planning of the functional countermeasure works and civil defence evacuation plan.

Research on Multiple Holes Grouting of Fractured Rock Mass

2012 ◽  
Vol 256-259 ◽  
pp. 547-551 ◽  
Author(s):  
Yong Xu ◽  
Wei Hong Peng
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Distinct Element ◽  
Fracture Aperture ◽  
Diffusion Distance ◽  
Fractured Rock Mass ◽  
Grouting Pressure ◽  
Universal Distinct Element Code ◽  
Distinct Element Code ◽  
Multiple Holes

Considering the seepage stress coupling of fractured rock mass, the multiple holes grouting problems were simulated to analyse the spread regularity by Universal Distinct Element Code(UDEC).The results show that the correlation between grouting pressure and the diffusion distance is positive, whereas the correlation between ground stress and diffusion distance is negative; With the raising of grouting holes, the diffusion distance is increasing and becoming more uniform in all directions, and the grout pressure and saturation is falling and attenuation amplitude is decreasing along the direction of grout diffusion; With the increasing of fracture aperture, the grout diffusion distance is increasing, and the grout pressure and saturation attenuation amplitude is decreasing along the direction of grout diffusion.

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