A new approach to estimate plastic region near tunnel considering excavation induced damage and in situ rock mass condition

2005 ◽  
Author(s):  
Myung Sagong ◽  
Jun Lee
Keyword(s):  
Rock Mass ◽  
Plastic Region ◽  
New Approach ◽  
Rock Mass Condition

In situ determination of a rock mass modulus using a high resolution tiltmeter

1996 ◽  
Vol 33 (2) ◽  
pp. 350-355 ◽  
Author(s):  
Bassam Saleh ◽  
Abdallah I Husein Malkawi ◽  
Pierre A Blum
Keyword(s):  
Rock Mass ◽  
High Resolution ◽  
Boussinesq Model ◽  
New Approach ◽  
Structural Work ◽  
Rock Mass Modulus ◽  
Elastic Rock ◽  
The Impact

A very high resolution tiltmeter (10–8 rad, 0.002 s) developed by P.A. Blum, in 1957 was used to establish a new approach to directly evaluate the in situ average elastic rock-mass modulus. Five tiltmeters were installed on the facades of the Louvre museum to study the deformations induced by internal structural work and by the impact of the Paris metro traffic movement. The measured data from the tiltmeter were used to determine the elastic rock modulus of the museum's foundation using the Boussinesq model. The results obtained by the developed approach are consistent with the typical elastic rock-mass modulus for the rock found in the museum's foundations. Key words: rock-mass modulus, tiltmeter, deformation, Boussinesq model.

Surrounding Rock Stability Analysis and Rock Burst Prediction of Underground Cavity in High In Situ Stress

2012 ◽  
Vol 594-597 ◽  
pp. 1174-1181
Author(s):  
Hai Yan Zang ◽  
Guang Di Wang
Keyword(s):  
Rock Mass ◽  
Rock Burst ◽  
Plastic Region ◽  
Damage Model ◽  
Average Energy ◽  
Stress Transfer ◽  
Surrounding Rock ◽  
Large Section ◽  
Diversion Tunnel

Based on Sidoroff isotropic elastic damage model, the damage deterioration constitutive equation was constructed for rigid and brittle rock mass. The excavation numerical simulation of a diversion tunnel with large section in Jinping hydro station was carried on. The displacement and stress evolution was analyzed considering stress transfer and dissipation of the tunnel surrounding rock mass. The stability evaluation parameters were put forward such as stress relaxation coefficient of surrounding rock mass, safety factor, the scale and distribution of plastic region of surrounding rock mass. The rock burst predication index was presented in viewpoint of energy such as sub-range statistic average energy release rate and sub-range statistic failure volume. The excavation methods for the diversion tunnel with large section were evaluated with multi criteria and the guideline for large section cavity in high in-situ stress was summarized.

scholarly journals The Effect of Selected Factors on Floor Upheaval in Roadways—In Situ Testing

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5686
Author(s):  
Piotr Małkowski ◽  
Łukasz Ostrowski ◽  
Łukasz Bednarek
Keyword(s):  
Compressive Strength ◽  
Rock Mass ◽  
Measurement Data ◽  
Complex Form ◽  
Study Results ◽  
Geological Conditions ◽  
The Stability ◽  
Rock Mass Condition ◽  
Mine Roadways

The phenomenon of the floor upheaval occurs in virtually every type of rock mass and at every depth, accompanying the process of excavation of tunnels and headings. Despite its inconvenience, it is rarely studied because of the complexity of the process and the multiplicity of the factors causing deformations in floor rocks. To quantify the effect of the selected factors on floor upheaval, this article presents an analysis of results of in situ measurements carried out in three coal mine roadways at 15 measuring stations. These measurements were taken over varying periods of time, between 129 and 758 days. Groundwater and fault zones intersecting the excavations were considered as the key factors that affect floor upheavals. Therefore, the measurement bases were located at local faults and sites of water inflow. To compare the results, the stations were also located where the rock mass was not exposed to any factors other than stresses resulting from the depth of the excavation. The excavations were driven in various rocks and were located at different depths from 750 to 1010 m. The analyses of the study results show that the floor upheaval always depends on time and can be described in polynomial form: ufl = a·t2 + b·t + c or by a power function: ufl = a·tb. However, the further regression analyses show that roadway’s floor upheaval can be expressed by a complex form using the key parameters determining the phenomena. In the absence of an impact of geological factors on the stability of the excavation, the floor upheaval depends on floor rocks compressive strength σc and Young’s modulus E: ln(ufl)=a·ln(tσc)−bE−c; in the case of rock mass condition affected by water depends on the rock compressive strength reduction after submerging rock in water σcs 6h: ufl=a·t0.5−bσcs 6hσc+c and in the case of fault depends on the fault’s throw f: ufl=a·t0.8+b·f1.2−c. Statistical analysis has shown that the matching of the models to the measurement data is high and amounts to r = 0.841–0.895. Hence, in general, the analysis shows that the floor upheaval in underground excavation in any geological conditions may grow indefinitely.

scholarly journals Neuroimmune Response Mediated by Cytokines in Natural Scrapie after Chronic Dexamethasone Treatment

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 204
Author(s):  
Isabel M. Guijarro ◽  
Moisés Garcés ◽  
Pol Andrés-Benito ◽  
Belén Marín ◽  
Alicia Otero ◽  
...  
Keyword(s):  
Prion Diseases ◽  
Global Approach ◽  
Profile Data ◽  
Dexamethasone Treatment ◽  
New Approach ◽  
Complex Interactions ◽  
Natural Scrapie ◽  
Anti Inflammatory

The actual role of prion protein-induced glial activation and subsequent cytokine secretion during prion diseases is still incompletely understood. The overall aim of this study is to assess the effect of an anti-inflammatory treatment with dexamethasone on different cytokines released by neuroglial cells that are potentially related to neuroinflammation in natural scrapie. This study emphasizes the complex interactions existent among several pleiotropic neuromodulator peptides and provides a global approach to clarify neuroinflammatory processes in prion diseases. Additionally, an impairment of communication between microglial and astroglial populations mediated by cytokines, mainly IL-1, is suggested. The main novelty of this study is that it is the first one assessing in situ neuroinflammatory activity in relation to chronic anti-inflammatory therapy, gaining relevance because it is based on a natural model. The cytokine profile data would suggest the activation of some neurotoxicity-associated route. Consequently, targeting such a pathway might be a new approach to modify the damaging effects of neuroinflammation.

In Situ Tests on Creep Behavior of Rock Mass with Joint or Shearing Zone in Foundation of Large-Scale Hydroelectric Projects

2004 ◽  
Vol 261-263 ◽  
pp. 1097-1102 ◽  
Author(s):  
Jian Liu ◽  
Xia Ting Feng ◽  
Xiu Li Ding ◽  
Huo Ming Zhou
Keyword(s):  
Rock Mass ◽  
Creep Behavior ◽  
Large Scale ◽  
Time Dependent ◽  
Three Gorges Project ◽  
Three Gorges ◽  
The Three Gorges ◽  
The Three Gorges Project

The time-dependent behavior of rock mass, which is generally governed by joints and shearing zones, is of great significance for engineering design and prediction of long-term deformation and stability. In situ creep test is a more effective method than laboratory test in characterizing the creep behavior of rock mass with joint or shearing zone due to the complexity of field conditions. A series of in situ creep tests on granite with joint at the shiplock area of the Three-Gorges Project and basalt with shearing zone at the right abutment of the Xiluodu Project were performed in this study. Based on the test results, the stress-displacement-time responses of the joints and basalt are analyzed, and their time-dependent constitutive model and model coefficients are given, which is crucial for the design to prevent the creep deformations of rock masses from causing the failure of the operation of the shiplock gate at the Three-Gorges Project and long-term stability of the Xiluodu arc dam.

scholarly journals An Unconventional Field Mapping Application: A Complete Opensource Workflow Solution Applied to Lithological Mapping of the Coatings of Cultural Heritage

2021 ◽  
Vol 10 (6) ◽  
pp. 357
Author(s):  
Niccolò Iandelli ◽  
Massimo Coli ◽  
Tessa Donigaglia ◽  
Anna Livia Ciuffreda
Keyword(s):  
Cultural Heritage ◽  
Coating Materials ◽  
Historical Building ◽  
New Approach ◽  
Photo Interpretation ◽  
Organization Management ◽  
Field Mapping ◽  
Lithological Mapping ◽  
Entire Amount

The conservation of a primary importance historical building requires organization, management, continuous updating, comparison, and visualization of a large amount of data of different nature and origin. In relation to these aspects the use of a GIS brings various advantages including single and univocal management of the entire amount of existing data in a relational, dynamic, updatable and queryable way. The integration of a mobile solution permits the updating of the dataset and checking on site all information. The workflow presented uses opensource solutions, desktop and mobile, which allows the creation of an unconventional lithological Field Mapping activity: starting from photo interpretation and in situ survey, all the coating materials (stone, etc.) of some monuments of primary historical and cultural interest have been mapped (i.e., Duomo di Firenze, Duomo di Prato). The product can be considered as a lithological cartography, vertically oriented, processed by field surveys, geognostic surveys and photo interpretation. All combined to create a “lithological” mapping of the coatings of the various monuments; the advantage is a new approach for conservation and restoration of Cultural Heritage. The proposed workflow involves a mobile solution, opensource, that allows the verification and management of the database in the field.

scholarly journals Non-dispersive UV Absorption Spectroscopy: A Promising New Approach for in-situ Detection of Sulfur Dioxide

2019 ◽  
Vol 7 ◽  
Author(s):  
Jan-Lukas Tirpitz ◽  
Denis Pöhler ◽  
Nicole Bobrowski ◽  
Bruce Christenson ◽  
Julian Rüdiger ◽  
...  
Keyword(s):  
Sulfur Dioxide ◽  
Absorption Spectroscopy ◽  
Uv Absorption ◽  
New Approach ◽  
Uv Absorption Spectroscopy ◽  
In Situ Detection

Analysis of TBM Tunnel Behavior in Jointed Rock Mass

2011 ◽  
Vol 90-93 ◽  
pp. 2033-2036 ◽  
Author(s):  
Jin Shan Sun ◽  
Hong Jun Guo ◽  
Wen Bo Lu ◽  
Qing Hui Jiang
Keyword(s):  
Rock Mass ◽  
Numerical Models ◽  
Jointed Rock ◽  
In Situ Stress ◽  
Jointed Rock Mass ◽  
Joint Orientation ◽  
Joint Spacing ◽  
Factors Affecting ◽  
Dip Angle

The factors affecting the TBM tunnel behavior in jointed rock mass is investigated. In the numerical models the concrete segment lining of TBM tunnel is concerned, which is simulated as a tube neglecting the segment joint. And the TBM tunnel construction process is simulate considering the excavation and installing of the segment linings. Some cases are analyzed with different joint orientation, joint spacing, joint strength and tunnel depth. The results show that the shape and areas of loosing zones of the tunnel are influenced by the parameters of joint sets and in-situ stress significantly, such as dip angle, spacing, strength, and the in-situ stress statement. And the stress and deformation of the tunnel lining are influenced by the parameters of joint sets and in-situ stress, too.

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