Papers by Author: Wen Zhao

Abstract: The ranging greater than 3m is not accorded with china engineering construction standardization association standard TECHNOLOGICAL SPECIFICATION FOR INSPECTION OF CONCRETE DEFECTS BY ULTRASONIC METHOD[CECS 21:200 (Transducer spacing is 2~3m). This paper studied large ranging of ultrasonic test mass concrete structure, and analyzed a project instance that was inspected the internal defects of mass concrete structures with various test methods, compared of those results. As detection is shown, first, with the test distance increased to 5.1m, the velocity of sound shows a linear trend of continuous development trend. Second, responds to improve of concrete strength, the velocity of sound increases, but not shows a linear trend. In addition, with the test distance increasing, concrete strength increases, but the velocity is down. A large ranging of ultrasonic test method was developed based on these observations.

Abstract: The non-pillar sublevel caving method is used in Iron Mine in Banshi. In the mining area, there are many folds and faults, the inclination of ore body changes greatly, and ore and rock are fragmentized. The tunnel often collapsed and the surrounding rock deformation was getting large during the construction stage. Using the data of tunnel surrounding rock deformation, we adopt the neural network method to set up the mapping relation between the tunnel surrounding rock deformation and the project factors, including tunnel deepness, tunnel dimension, measuring time and surrounding rock quality. The analyzing results show that the maximum error between the forecast and the testing data is 13%, which indicates that this method is useful and feasible to the mining engineering. Key words: rock pressure; measure, deformation of the tunnel surrounding rock; neural network; data normalization; mapping

Abstract: The construction procedure of subsurface excavation method is very complex. In order to obtain the regular pattern that the construction process of pile hole may influence the ground surface subsidence, the author use Lizheng software to analysis the construction parameter of excavation, installation and removal of the support, back building etc. Using the finite element analysis method, the author simulate the surface subsidence. Comparing the simulation results with the measured data, the author get the regular patter of surface subsidence and the envelope diagram of Internal force and displacement of the retaining pile.

Abstract: The selection of material parameters relates to the excavation stability of the underground caverns. However, back analysis is an efficient method to evaluate mechanical parameters. Given the defects of BP neural network, such as low capability of generalization and long training time, by using GA, which have global optimization ability to optimize the BP neural network weights. The parameter of surrounding rock was designed by uniform and orthogonal method, not only reduced the iterative time also improved the accuracy of the prediction. The proposed method is further illustrated with its application to the underground cavern of Lvchunba railway tunnel. Based on the surrounding rock’s parameters obtained by back analysis, the displacement of the surrounding rock was predicted. The results showed that the error between numerical calculation value and actual monitoring value was 13.2%,-8.3%,-8.9%,9.4% respectively.

Abstract: The hybrid fiber reinforced concrete containers for keeping nuclear waste (NWSC) were made by the concrete which mixed polypropylene fibers (0.9kg/m3) and 20mm basalt fiber (2.5kg/m3). The carbonation depth model was established by analyzing carbonation depth of ordinary concrete and hybrid fiber reinforced concrete that through the accelerated carbonization testing. And then two kinds of different concrete NWSC carbonation life were predict according to the similarity theory. The results show that the carbonation life of hybrid fiber reinforced concrete NWSC is 67％ higher than ordinary concrete ones, The addition of fiber can improve the resistance ability of concrete. The hybrid fiber reinforced concrete storage container can meet the requirements of the service life-300a when the thickness of the protective layer is more than 32mm.

Abstract: The control of concrete crack is a complicated and difficult problem for civil engineering. It is more difficult to control the crack of the concrete poured in winter. Thorough the analysis of the construction of Shenyang subway in winter, a combination of methods are applied. Frost proof and decreasing the temperature stress of concrete are considered together. The combination of antifreezing measures and decreasing the temperature stress of concrete make the construction quality arrive a satisfying level.

Abstract: For subway tunneling in urban underground, high safty of construction is needed.However, the safty and rationality of excavating plan are forecasted difficultly because of consealment. Based on the Zhang-Shen tunnel construction of Shenyang subway, bench method, single side-wall heading excavation method and CD excavation method are numerical simulated; according to the numerical calculation results and the constructing process, bench method is adopted; the ground settlement caused by excavation monitored during excavating is in the allowed range and the tunnel is safe during excavating.

Abstract: The boiler steel structure is the main parts of the boiler, its stability directly determines the normal operation of the boiler and the security of the surrounding environment. For analyzing the boiler steel structure, first respectively using matrix displacement method, energy method and the empirical formula method to calculate the periodic of the boiler steel structure; then using the bottom shear method and the mode-superposition response spectrum method to calculate the shear and the axial force of the boiler steel structure in same situation, and through comparing the results to gain the correction coefficient of the mode-superposition response spectrum for the engineering practice and discussing the calculation of the boiler steel structure under earthquake using mode-superposition response spectrum method. Providing the theoretical basis for the seismic design, the reinforcement and the maintenance of the boiler steel structure.

Abstract: Discuss monitoring way of slope sliding of ANGANG open mine on Robotic Measuring System TM30 technology and processing data’s method, according to survey speciafication of deformation observation, analyses deformation result and compares it with speciafication of deformation observation, reports it to the mine company to insure safety and stability of mine produce. Deformation monitoring on Robotic total station TM30 that is Observation flexible, high precision and high efficiency is worth spreading.

Abstract: Soil Pressure in the chamber is one of the important construction parameters. It is very important to set up reasonable soil Pressure in the chamber for controlling the ground settlement, promoting the peed of drift and lowering the cost of drifting. Take some subway tunnel for example, and carry out the 3D finite element simulation. In order to investigate the influence on ground settlement from soil pressure in the chamber, take 15% of the progressive increase in earth pressure to simulate over-balance conditions and also take 15% of the progressive decrease in earth pressure to simulate under-balance conditions. The results indicated that while the soil pressure achieves equilibrium, the swell and the settlement are all small. While over-equilibrium, the swell increases, on the contrary, the settlement increases while under-equilibrium. So, a good control over the soil pressure is one of the most effective therapies for decreasing the ground settlement.