scholarly journals Study on Dynamic Response Characteristics of Saturated Asphalt Pavement under Multi-Field Coupling

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 959 ◽  
Author(s):  
Yazhen Sun ◽  
Rui Guo ◽  
Lin Gao ◽  
Jinchang Wang ◽  
Xiaochen Wang ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Asphalt Pavement ◽  
Water Pressure ◽  
Moving Load ◽  
Transverse Stress ◽  
Middle Point ◽  
Mechanical Coupling ◽  
Temperature Load

To study the dynamic response of saturated asphalt pavement under moving load and temperature load, 3-D finite element models for asphalt pavements with hydro-mechanical coupling and thermal-hydro-mechanical coupling were built based on the porous media theory and Biot theory. First, the asphalt pavement structure was considered as an ideal saturated fluid–solid biphasic porous medium. Following this, the spatial distribution and the change law of the pore-water pressure with time, the transverse stress, and the vertical displacement response of the asphalt pavement under different speeds, loading times, and temperatures were investigated. The simulation results show that both the curves of the effective stress and the pore-water pressure versus the external loads have similar patterns. The damage of the asphalt membrane is mainly caused by the cyclic effect of positive and negative pore-water pressure. Moreover, the peak value of pore-water pressure is affected by the loading rate and the loading time, and both have positive exponential effects on the pore-water pressure. In addition, the transverse stress of the upper layer pavement is deeply affected by the temperature load, which is more likely to cause as transverse crack in the pavement, resulting in the formation of temperature cracks on the road surface. The vertical stress at the middle point in the upper layer of the saturated asphalt pavement, under the action of the temperature load and the driving load, shows a single peak.

scholarly journals Effect of Clogging on the Permeability of Porous Asphalt Pavement

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Yaolu Ma ◽  
Xianhua Chen ◽  
Yanfen Geng ◽  
Xinlan Zhang
Keyword(s):  
Pore Water ◽  
Evaluation Method ◽  
Pore Water Pressure ◽  
Asphalt Pavement ◽  
Water Pressure ◽  
Asphalt Pavements ◽  
Porous Asphalt ◽  
Capacity Coefficient ◽  
Drainage Capacity ◽  
High Level

The purpose of this paper is to report on the drainage of porous asphalt pavement evaluation method suited for use in analyzing clogging effect. To preliminarily reveal the decrease in permeability caused by clogging of permeable asphalt pavement, an innovative device was proposed to evaluate the anisotropy of permeability influenced by clogging, and the maximum drainage capacity without surface ponding can be obtained when the supplied water was controlled. Then, finite element models for asphalt pavements with hydromechanical coupling were proposed based on porous media theory and Biot’s theory. The variation in pore water pressure was simulated by considering the decrease in voids and the increase in clogging grains. The results indicate that the internally retained water should not be ignored because the semiconnected voids were filled with water rapidly at the beginning of permeability tests. To avoid surface ponding, the drainage capacity coefficient (DCC) can be used to evaluate the maximum drainage capacity (MDC) influenced by clogging. Moreover, the pore water pressure increased due to the reduction in voids and a high level of clogging. In addition, the peak value of pore water pressure is also affected by the upper-layer height of the pavement. Under the action of clogging and driving load, a reasonable thickness of the upper layer and a drainage evaluation should be considered to improve road safety.

scholarly journals Progressive Failure and Fracture Mechanism of Sandstone under Hydraulic-Mechanical Coupling

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Yingming Li ◽  
Gang Liu ◽  
Tao Qin ◽  
Zhupeng Jin ◽  
Chengxing Zhao ◽  
...  
Keyword(s):  
Pore Water ◽  
Fracture Mechanism ◽  
Pore Water Pressure ◽  
Progressive Failure ◽  
Water Pressure ◽  
Confining Pressure ◽  
Experimental Results ◽  
Type I ◽  
Volume Deformation ◽  
Mechanical Coupling

Hydraulic coupling often leads to progressive rock failure accidents. Mechanical tests were performed over a range of combined pore water pressure and confining pressure stress path conditions to study the progressive failure characteristics of sandstone under hydraulic-mechanical coupling and explore the crack initiation and pore water fracture mechanism. The closure stress and damage stress were determined by the axial deformation stiffness and volume deformation stiffness. The experimental results indicate that confining pressure is the main controlling factor in the crack propagation stage, and pore water pressure enhances crack evolution. With increasing effective confining pressure, the effective peak deviatoric stress strongly increases and the characteristic stress increases linearly. The initiation stress and damage stress decrease with increasing pore water pressure. The moduli in stages I, II, and III are similar to the law of the transverse and radial deformation ratio with notable differences in stage IV. The fracture trend angle was determined by the ratio of axial crack strain and radial crack strain. Compared with the experimental results, the internal cracks in the sandstone samples are mainly type-II cracks, and type-I cracks are also locally present. After stress damage, the cracks expand and extend at an angle close to the real fracture.

Analysis of One-Dimensional Thermal Consolidation of Saturated Soil with and without Thermo-Mechanical Coupling

2012 ◽  
Vol 594-597 ◽  
pp. 335-338
Author(s):  
Xue Shen ◽  
Rui Qian Wu
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Saturated Porous Medium ◽  
Water Pressure ◽  
Saturated Soil ◽  
Excess Pore Water Pressure ◽  
One Dimensional ◽  
Mechanical Coupling ◽  
Thermal Consolidation ◽  
Excess Pore

Based on a one-dimensional thermal consolidation formulation with and without thermo-mechanical coupling of saturated porous medium, problems of one-dimensional thermal consolidation of saturated soil were investigated. For the condition with instantaneous constant surface temperature and uniform initial pore-pressure, analytical solutions of excess pore-water pressure and temperature increment were derived respectively by the method of finite Fourier transform and inverse transform. A relevant computer program was developed, and the excess pore-water pressure was compared in detail. The results show that the thermo-mechanical coupling item in the thermal consolidation equation can be ignored.

scholarly journals Mechanical properties and acoustic emission characteristics of granite under thermo-hydro-mechanical coupling

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4585-4596
Author(s):  
Xin-Zhong Wang ◽  
Dong Wang ◽  
Zhe-Wei Wang ◽  
Xiao-Juan Yin ◽  
Xue-Jun Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Acoustic Emission ◽  
Elastic Modulus ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Thermal Cracking ◽  
Confining Pressure ◽  
Mechanical Coupling ◽  
Increasing Temperature

Exploring the mechanical properties and thermal cracking characteristics of rock under thermo-hydro-mechanical coupling in detail is of great importance for the safe excavation and stability of deep rock engineering. The mechanical properties and thermal cracking characteristics of granite under burial depths of 1000 m (confining pressure of 25 MPa) and 1600 m (confining pressure of 40 MPa) at a temperature of 110?C and a pore water pressure of 10 MPa were studied. The results show that the elastic modulus decreases with increasing temperature under a confining pressure of 25 MPa, whereas under a confining pressure of 40 MPa, the elastic modulus increases with increasing temperature. As the pore water pressure increases, the elastic modulus decreases slightly. Poisson?s ratio increas?es with increasing temperature below 40?C but decreases from 50-110?C. Pois?son?s ratio increases as pore water pressure increases. During the heating process, acoustic emission activity is first detected at 30-40?C and is relatively stable from 40-90?C. The acoustic emission activity increases sharply at 90-110?C, and the thermal cracking threshold of granite under thermo-hydro-mechanical coupling is approximately 95?C.

Experiment Study of Rock Damage and Permeability Meso-Mechanical Coupling Failure Model under Complex Condition

2010 ◽  
Vol 40-41 ◽  
pp. 354-360
Author(s):  
Ji Kun Zhao
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Confining Pressure ◽  
Coupling Mechanism ◽  
Mechanism Analysis ◽  
Force Transmission ◽  
Mechanical Coupling ◽  
Compression Sample ◽  
Weak Part

Pore water pressure and the changes of crustal deformation, fault rupture and seismic activity has important influence. So the pore water pressure and load rock stress – hydro-mechanical coupling mechanism is very important. This paper mainly studies the rock specimens of hydraulic crack damage simulation. This study found: with the increase of the axial compression, sample is on the surface crack. Crack characteristics is smooth and continuously expanding. With the load increasing at the same time, the number of samples is also increased damage elements. The sample was through the cracks. This is due to the effect of water pressure to reduce the size of confining pressure .From the failure mechanism analysis, the distribution of stress non-uniform material will not uniformity, reflected in the actual rock because of the grain and the defects of the random distribution. When the load, the composition of force transmission effect of different deformation and stress in rock, the internal non-uniform stress concentration, local, it will directly cause the weak part, and micro cracks generated change the failure mode of materials.

TIME TO THE END OF PRIMARY CONSOLIDATION (EOP) OF SOFT CLAYEY SOILS: CONCERNING THE EFFECT OF ATTERBERG’S LIMIT AND CYCLIC LOADING HISTORY

2019 ◽  
Vol 128 (2B) ◽  
pp. 29-41
Author(s):  
Trần Thanh Nhàn
Keyword(s):  
Cyclic Loading ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Clayey Soils ◽  
Loading History ◽  
Cyclic Shear ◽  
Wide Range ◽  
Primary Consolidation ◽  
Time Required

In order to observe the end of primary consolidation (EOP) of cohesive soils with and without subjecting to cyclic loading, reconstituted specimens of clayey soils at various Atterberg’s limits were used for oedometer test at different loading increments and undrained cyclic shear test followed by drainage with various cyclic shear directions and a wide range of shear strain amplitudes. The pore water pressure and settlement of the soils were measured with time and the time to EOP was then determined by different methods. It is shown from observed results that the time to EOP determined by 3-t method agrees well with the time required for full dissipation of the pore water pressure and being considerably larger than those determined by Log Time method. These observations were then further evaluated in connection with effects of the Atterberg’s limit and the cyclic loading history.

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