Analysis on the Ultimate Pullout Force of Prestressed Cable Based on Nonlinear Mohr Strength Criterion

2012 ◽  
Vol 430-432 ◽  
pp. 1369-1372
Author(s):  
Xiao Yan Luo ◽  
Wei Ping Liu
Keyword(s):  
Compressive Strength ◽  
Rock Type ◽  
Strength Criterion ◽  
Pullout Force ◽  
Grouting Pressure ◽  
Ultimate Equilibrium ◽  
Engineering Practices ◽  
Prestressed Cable

Based on parabolic Mohr strength criterion and the ultimate equilibrium principle, the ultimate pullout force of prestressed cable is studied. The ultimate pullout force of prestressed cable is related to the rock type, the shapes of rapture surface, grouting pressures and compressive strength of rock, etc. The results show that the grouting pressure increases, the ultimate pullout force of prestressed cable increases also. It can provide theoretical supports for some prestressed cable engineering practices.

Study on the Ultimate Pullout Force of Prestressed Cable Based on Triple Shear Unified Yield Criterion

2012 ◽  
Vol 594-597 ◽  
pp. 840-843
Author(s):  
Xiao Yan Luo ◽  
Wei Ping Liu
Keyword(s):  
Principal Stress ◽  
Yield Criterion ◽  
Intermediate Principal Stress ◽  
Stress Effect ◽  
Pullout Force ◽  
Grouting Pressure ◽  
Effect Parameter ◽  
Ultimate Equilibrium ◽  
Intermediate Principal Stress Effect ◽  
Prestressed Cable

Based on the triple shear unified yield criterion and the ultimate equilibrium principle, the ultimate pullout force of prestressed cable is studied. The ultimate pullout force of prestressed cable is related to the rock type, the shapes of rapture surface, grouting pressures and compressive strength of rock, etc. The results show that the intermediate principal stress effect parameter b have influences on the ultimate pullout force of prestressed cable. With the increase of the intermediate principal stress effect parameter b, the ultimate pullout force of prestressed cable increases too. When the grouting pressure increases, the ultimate pullout force of prestressed cable increases also.

Investigation of Point Load Index Using Novel Discrete Based Model

2016 ◽  
Vol 846 ◽  
pp. 348-353
Author(s):  
Somayeh Behraftar ◽  
Joshua Heslin ◽  
S. Galindo Torres ◽  
Alexander Scheuermann
Keyword(s):  
Compressive Strength ◽  
Material Properties ◽  
Mechanical Model ◽  
Rock Type ◽  
Correlation Factor ◽  
Point Load ◽  
Load Test ◽  
Point Load Index ◽  
Bonded Particles ◽  
The One

In this study, a micro-mechanical model is developed to study the correlation of the point load index in rocks with uniaxial compressive strength (UCS) tests. The model is represented by an array of bonded particles simulated by a novel discrete based model, which was introduced by the authors previously. The point load test (PLT) is performed in the field on rock samples to classify and estimate the UCS of a rock type via the index-to-strength correlation factor k. Numerical analyses, such as the one presented in this work, will serve to close the knowledge gap concerning the correlation between k, UCS and other material properties of rocks.

scholarly journals A New Evaluation Method for the Uniaxial Compressive Strength ahead of the Tunnel Face Based on the Driving Data and Specification Parameters of TBM

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Yuexiu Wu ◽  
Chishuai Ma ◽  
Xianjun Tan ◽  
Dianseng Yang ◽  
Hongming Tian ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Evaluation Method ◽  
Hard Rock ◽  
Rock Type ◽  
Soft Rock ◽  
Tunnel Face ◽  
Diversion Tunnel ◽  
Proposed Model ◽  
High Prediction

Uniaxial compressive strength (UCS) is a very important fundamental mechanical parameter for TBM construction. In this work, a predictive model of UCS was proposed according to the TBM parameters including torque, penetration, cutter number, and cutter diameter. The parameter of the new proposed model was established by fourteen existed TBM tunnels’ construction data. To describe the relationships of UCS with PLSI of the Murree tertiary hard rocks, regression analyses have been conducted and a fitting equation with high-prediction performance was developed. Validation from the data of Neelum–Jhelum (NJ) TBM diversion tunnel were carried out. The absolute errors between predictive UCS and experimental UCS were presented. Through comparison, it can be concluded that the proposed calculation equation of UCS has a high accuracy for a certain rock type with UCS from 50 MPa to 200 MPa. For special hard rock or soft rock, a new calculation equation between UCS and TBM parameters should be studied furthermore.

Laboratory Investigation on the Fresh, Mechanical, and Durability Properties of Roller Compacted Concrete Pavement Containing Reclaimed Asphalt Pavement Aggregates

2019 ◽  
Vol 2673 (10) ◽  
pp. 652-662 ◽  
Author(s):  
Solomon Debbarma ◽  
Surender Singh ◽  
G. D. Ransinchung R.N.
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Abrasion Resistance ◽  
Asphalt Pavement ◽  
Strength Criterion ◽  
Concrete Pavement ◽  
Reclaimed Asphalt Pavement ◽  
Split Tensile Strength ◽  
Reclaimed Asphalt ◽  
Roller Compacted Concrete

The present study evaluates the potential and suitability of different fractions of reclaimed asphalt pavement (RAP) for roller compacted concrete pavement (RCCP) mixes. Natural coarse and fine aggregates were replaced, partially and in combination, by coarse RAP, fine RAP, and combined RAP for preparation of RCCP mixes. The considered properties to determine the optimum RAP fraction and its proportion for RCCP were fresh density and water demand, compressive strength, flexural strength, split tensile strength, porosity, water absorption, abrasion resistance, and performance in aggressive environments of chloride- and sulfate-rich ions. It was observed that inclusions of all the fractions of RAP considered could reduce the strength related properties of RCCP mixes significantly at all curing ages. However, fine RAP mixes were found to exhibit better strength properties than coarse RAP and combined RAP mixes. It was also observed that none of the RAP mixes could achieve the recommended compressive strength criterion of 27.6 MPa, however, they exhibited enough flexural strength to replace a fraction of conventional aggregates, individually or in combination, for construction using RCCP. In fact, 50% coarse and 50% fine RAP mixes had higher flexural strength than the target laboratory mean strength of 4.3 MPa. Similarly, these mixes were found to have sufficient abrasion resistance and could be included in RCCP (surface course) to be constructed in areas having high concentrations of chloride and sulfate ions. Additionally, the results also indicated that higher proportions of fine RAP may be suggested for RCCP mixes to be laid in sulfatic environments.

scholarly journals Study of the Mechanism of Fracture Grouting in Deeply Buried Rock Strata Based on Bingham Fluid Slurry

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Xiangyang Liu ◽  
Hua Cheng ◽  
Jian Lin ◽  
Chuanxin Rong ◽  
Mingjing Li ◽  
...  
Keyword(s):  
Flow Rate ◽  
Pressure Coefficient ◽  
Single Fracture ◽  
Time Varying ◽  
Grouting Pressure ◽  
Fracture Grouting ◽  
Material Fracture ◽  
Rock Mechanical Properties ◽  
Engineering Practices ◽  
Rock Strata

In view of the fact that the theory of fracture grouting in deeply buried rock strata seriously lags behind engineering practices, a circular fracturing diffusion model of a single fracture was established by considering numerous influencing factors of deeply buried rock strata, such as the crustal stress characteristics, rock mechanical properties, and time-varying characteristics of the serous viscosity. By setting the stress intensity factor KI equal to the material fracture toughness KIC at the fracture tip as the criterion for fracturing, the diffusion equation for the fracture grouting was derived and verified experimentally. Theoretical analysis shows that the fracture grouting pressure P0 is linearly proportional to the depth of the strata H and the lateral pressure coefficient k. The time-varying characteristics of the serous viscosity have an important influence on the grouting pressure and the diffusion radius. Its early impact is small, while its later impact is large. The diffusion radius of the grouting is indirectly proportional to the grouting pressure and the grouting flow rate. In order to increase the diffusion radius of the grouting, the grouting pressure and the grouting flow rate should be increased simultaneously. In order, the main factors influencing the diffusion radius of the fracture grouting are the time-varying characteristics of the serous viscosity, the grouting pressure, the grouting flow rate, and the depth of the strata.

scholarly journals Evaluation of Chloride Resistance of Early-Strength Concrete Using Blended Binder and Polycarboxylate-Based Chemical Admixture

2020 ◽  
Vol 10 (8) ◽  
pp. 2972 ◽  
Author(s):  
Taegyu Lee ◽  
Jaehyun Lee
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Portland Cement ◽  
Chloride Ion ◽  
Strength Criterion ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Characteristic Strength ◽  
Early Strength

The mixing proportions of concrete were examined with regard to the durability performance and early strength in coastal areas. Research was conducted to improve the C24 mix (characteristic strength of 24 MPa). C35 concrete (characteristic strength of 35 MPa) was selected as a comparison group, as it exhibits the minimum proposed strength criterion for concrete in the marine environment. To secure the early strength of the C24 concrete, 50% of the total ordinary Portland cement (OPC) binder was replaced with early Portland cement (EPC); and to provide durability, 20% was substituted with ground granulated blast-furnace slag (GGBS). In addition, a polycarboxylate (PC)-based superplasticizer was used to reduce the unit water content. The compressive strength, chloride ion diffusion coefficient, chloride penetration depth, and pore structure were evaluated. After one day, the compressive strength improved by 40% when using EPC and GGBS, and an average increase of 20% was observed over 91 days. EPC and GGBS also reduced the overall porosity, which may increase the watertightness of concrete. The salt resistance performance was improved because the rapid early development of strength increased the watertightness of the surface and immobilization of chloride ions, decreasing the chloride diffusion coefficient by 50%.

Synthetic Melted Rock-Type Wasteforms

1994 ◽  
Vol 353 ◽  
Author(s):  
Igor A Sobolev ◽  
Sergey V Stefanovsky ◽  
Fyodor A Lifanov
Keyword(s):  
Compressive Strength ◽  
Electron Probe ◽  
Rock Type ◽  
Ceramic Materials ◽  
Induction Melting ◽  
Cold Crucible ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Ceramic Materials ◽  
Infra Red

AbstractGlass-ceramic materials based on sphene, pyroxenes, apatite as well as various SYNROC formulations have been produced through melting in a laboratory electrically-heated furnace and inductive-heated melter (“cold crucible”). Materials prepared were investigated by X-ray diffraction analysis, electron-probe microanalysis, infra-red and EPR spectroscopies. Basic properties such as leach rates of radionuclides, density and compressive strength have been determined. Melted SYNROC-B and C phase compositions produced by induction melting are similar to hot-pressed SYNROC.

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