Papers by Author: Tai Quan Zhou

Abstract: The calculation of truss deformation under static loading is studied in this paper. First, an experiment was conducted to get the truss deformation for calibration. Second, the deformation was calculated by the principle of virtual work of structural mechanics and by Ansys. The calculated results agree well with the test result. Finally, some suggestions are presented to the calculation of more complicated truss structures.

Abstract: Limit bearing capacity of foundation soil was studied in the paper using slip line method. Slip line results are found to be consistent with the results calculated by Terzaghi theoretical formula and Hansen theoretical formula. Then the influence of factors such as cohesion and friction angle is studied under complete smooth or complete tough conditions. The results show that in a certain range, limit bearing capacity of foundation increases with the increase of C₀, Φ. Limit bearing capacity of foundation under complete smooth condition is lower than the complete tough one.

Abstract: Normally consolidated subgrade limit bearing capacity of foundation soil was studied in the paper using slip line method. Slip line results are found to be consistent with the results calculated by Terzaghi theoretical formula and Hansen theoretical formula. Then the influence of cohesion, friction angle for normally consolidated subgrade is studied under complete smooth or complete tough conditions. The results show that the normally consolidated subgrade limit bearing capacity increases linearly with the increase of k, γ, while it increases nonlinear with the increase of Φ and the increasing growth rate improves with increasing value of Φ.

Abstract: The research uses the method of three-dimensional finite element analysis combined with the actual project application to study the slope reinforced by anti-slide pile. The research analyses the influence of reinforcement that the anti-slide exert on the soil and shows the changes of the sliding surface properties by establishing the finite element numerical model. The conclusion can be made that the ABAQUS finite element method is visual and practical. The study is of great benefit to the actual engineering.

Abstract: Polypropylene fiber reinforced concrete can improve the common concrete flexibility and it is beneficial for interaction between concrete lining structure and rock mass. The use of fiber reinforced concrete with wet sprayed concrete technique can improve the concrete lining structure construction quality and improve the rock mass self-bearing capacity. The wet-sprayed fiber reinforced concrete is first introduced in Jinhuashan railway tunnel early stage lining structure within soft and weak rock mass. The design of Jinhuashan railway tunnel lining structure using fiber reinforced concrete is introduced and the requirement of material used is explained. To evaluate the lining effect using wet-sprayed fiber reinforced concrete, the online monitoring method is used to measure the rock mass pressure and the concrete lining layer stress for both the experimental tunnel sections and comparison tunnel section. The monitoring data result shows that the rock mass pressure in experimental section is even distribution with lower rock mass pressure and lower concrete lining layer stress. The value of rock mass pressure and tunnel lining layer stress in comparison tunnel section is a little higher than that in experimental tunnel section. The experimental tunnel section using fiber reinforced concrete has good lining effect.

Abstract: The wet sprayed concrete technique has good virtue of improving the working condition within the tunnel, fewer reflective concrete loss and higher sprayed concrete quality. The concrete mixed with polypropylene fiber could improve the concrete inner structure, the flexural strength, tensile strength and anti-penetrating ability. The application of the wet sprayed polypropylene fiber reinforced concrete in the construction of tunnel lining structure could improve the stability of tunnel rock mass. The nonlinear finite element analysis is performed on rock mass stability of the railway tunnel lining structure and the rock mass stability is analyzed both for the un-lining tunnel and the lining tunnel. The computation result shows that the rock mass plasticity zone distribution with the lining structure is fewer than that without lining structure. To measure the deformation behavior, tunnel deformation measurement sensors are installed in the railway tunnel transverse section. The measured railway tunnel deformation result also shows that the lining structure deforms little and the rockmass is in stable state.

Abstract: Different kinds of fiber are used to reinforce the concrete to improve the concrete mechanical properties. The high modulus and high flexibility fibers are often used to reinforce in the cement base, which leads to the higher performance compound cement based materials. In the paper, the carbon fiber and glass fiber material are used as flexibility reinforced materials. The polypropylene fiber and the polyethylene fiber are used as strength reinforced materials. The combinations of the flexibility reinforced fiber and strength reinforced fiber are chosen as C-P HF (Carbon and Polypropylene Hybrid Fiber) and G-Pe HF (Glass and Polyethylene Hybrid Fiber). The concrete mixture ratio and the fiber-reinforced amount are determined to the author’s previous study. The relationship between compressive strength, flexural strength and length/diameter aspect ratio of fiber for the carbon and polypropylene hybrid fiber reinforced concrete (C-P HFRC), and for the glass and polyethylene hybrid fiber reinforced concrete (G--Pe HFRC) was tested and discussed. The testing results show that length/diameter aspect ratio of fiber obviously affects the flexural strength of C-P HFRC and G-Pe HFRC, though the compressive strength is slightly affected by the length-diameter aspect ratio.

Abstract: The parametric variational principle adopts the extreme variational idea in the modern control theory and uses state equations deduced from the constitutive law to control the functional variation, which is an effective solution to the nonlinear equations. Based on the fundamental equations of elasto-plasticity coupled damage problem, the potential functional of elasto-plasticity is constructed. Also the state equations with approximation of damage evolution equation and load functions are constructed in the paper. The solution of elasto-plasticity damage problem can be deduced to solve problem of the minimum potential energy function under the restriction of state equations. Thus the parametric variational principle for coupled damage is proposed. The variational principle has the virtue of definite physical meaning and the finite element equations are presented in the article to facilitate the application of parametric variatioal principle, which is easy to program on computer. Using the method mentioned in the article, a numerical calculation is carried out and the calculation result shows that the method is efficient for solving elasto-plasticity damage problem.

Abstract: The finite element analysis fully coupled fatigue damage evolution is implemented on the user subroutine UMAT of the finite element software ABAQUS. The fully coupled method developed with damage mechanics and the finite element analysis is performed on calculation of fatigue damage accumulation of the critical welded member in the Tsing Ma Bridge. The calculated result shows that the fatigue damage in the critical welded member is accumulated in the region of toe of welding. The value of faitgue life calculated by the fully coupled method is smaller than that by the uncoupled method, which suggests that there exists interaction between the fatigue damage evolution and the structural response. The linear Miner’s Law is widely used however conservative for the evaluation of fatigue life of bridge on service. The above results provide feasible method for accurate evaluation of fatigue damage in bridge components based on the hot spot stress analysis and the damage mechanics theory.

Abstract: The twin shear strength criterion has been proposed to consider the intermediate principal stress effect on the rock mass strength. The unified rock mass strength criterion could consider the intermediate principal stress effect on the rock mass strength. The unified rock mass elasto-plastic material model is implemented in ABAQUS user interface. As a case for study, the stability analysis of Dongjusi railway tunnel within hard rock mass is studied using the unified rock mass strength material. For comparison, the Hoek-Brown empirical strength criterion is also chosen for the rock mass material modeling. The computation results show that the plastic zone calculated using the unified rock mass strength criterion is smaller than that using the Hoek-Brown empirical strength criterion. The railway tunnel lining structure is designed according to the unified rock mass strength criterion and greatly makes use of the rock mass potential strength, which decreases engineering cost.