Advanced Materials Research Vols. 1079-1080

Abstract: Afterthe construction of subway main structure, in order to realize route adjustmentof alignment and gradient, it needs to survey the cross-section of subwaytunnel. Compared with conventional measuring methods, 3D laser scanning has thecharacteristics of non-contact measurement and can collect space 3D point clouddata with high density, this can improve the working efficiency for the subwaycross-section surveying. Based on the Leica Scanstation 2 scanners this paperanalyzed the 3D laser scanning point cloud data collection procedures and dataprocessing, expounded the subway cross-section surveying method based on pointcloud data; analyzed the feasibility of 3D laser scanning technology in theapplication of tunnel cross-section surveying based on the field validationdata. The results show that the cross-section measured by this method can meetthe technical requirements of route adjustment of alignment and gradient.

Abstract: With the continuous development of the level of China's political, economic and social, the construction industry also obtained great progress. At the same time, the quality problems of all kinds of building has become a very serious problem which restricting the expansion of the scale of the enterprise. Along with the global integration, exchanges between domestic and foreign construction companies are becoming more and more frequent. The quality issues is in relation to the future of the construction industry. Only to deal with this problem, we can win in the international competition of the company. In the future for a long period of time, the construction industry will have a greater impact on the national economy of our country. If we can not solve the fundamental problem restricting the development of construction industry, the development of this industry will not sustainable. There is a very serious problem In the course of engineering construction which is the crack control of reinforced concrete structures. If this problem can be solved, we can produce a relatively good effect in the development of China's construction industry.

Abstract: Flow around a circular cylinder is a classical problem in fluid mechanics. The flowing problem about three tandem cylinders with different diameter is numerical simulated by a finite volume method. Through the simulation, the variations of flow field with different distance between the adjacent cylinder and different Reynolds number are investigated. The simulation result shows that three tandem cylinders with different diameter can evidently small columns minish width and aggrandize length of cylinder wakes compared with single cylinder.

Abstract: Nowadays construction waste piles. For this phenomenon , this paper studied the mortar activity under different dosage of construction waste brick powder . The results show that with the increase of construction waste material content of brick powder, the mortar strength plummet .

Abstract: Concrete bridges on high-speed railway are usually constructed with high strength concrete. Because of shrinkage of concrete, large stress and deformation always appear in construction and operation process of bridges. It even leads to concrete cracking. So as to guarantee the safety of structures and smoothness of tracks, correct calculation of concrete shrinkage effect must be done. Concrete shrinkage effect is a very complex non-stress strain problem which is influenced by numerous factors and difficult to calculate. According to the factors considered from different emphasis aspects, a variety of patterns or specifications are formed based on different domestic and foreign models of concrete shrinkage calculation. Combined with the construction of Jiangshan Harbor Bridge (75+2×135+75) m prestressed concrete continuous beam bridge on Hangzhou-Changsha high-speed railway, concrete shrinkage field tests and measurements were carried in which the same mix of high strength concrete as that of the bridge was used. The results of tests and measurements were compared with results of different theoretical models. The effects of high strength concrete shrinkage on high-speed railway concrete bridges were studied and some useful conclusions were obtained.

Abstract: Residential area greening is an important part of urban greening, close to the residents, the most closely relationship with residents' daily life, it is the improvement of the quality of living environment, improve people's physical and mental health is very important. Residential area greening level, is an important symbol of urban modernization. Residential green space's most widely distributed in the urban landscape green space system, is the crucial aspect of common greening, is an important part of the urban ecological system.

Abstract: Grout-filled mechanical splice system is one of the most important technologies for precast construction. However, due to the high cost of grouted sleeve in Chinese construction market, the implementation of this technology is hindered. In this study, a new type of grouted sleeve was developed with standard seamless steel pipe by cold rolling depression. Utilizing this sleeve, eight coupler specimens were prepared and tested under incremental tensile load and cyclic load. The results indicate that all the specimens provided satisfactory behaviour of which the ultimate tensile strength exceeded the required loading capacity specified in ACI318 and JGJ107. The inner cavity configuration of the grouted sleeve has great influence on the confining mechanism of the splice and on the strain distribution in the sleeve. Because the compressive strength of grout is greatly higher than its tensile strength, the slope of the load-strain response curve of the sleeve under tensile load is lower than it under compressive load.

Abstract: Finite element method has been used to study the behavior of soil excavation. The solutions were generally obtained assuming linear elastic soil behavior. However, this paper treats the soil as an elastic-plastic medium. The simulation techniques used in the braced field excavation are presented first and then, in order that a converged solution can be obtained, an iteration solution technique called the mixed stiffness method is used in the incremental nonlinear finite element analysis of the field problem where the soil behavior is simulated as elastic-plastic by employing the Drucker-Prager model. The solution techniques and procedure presented can be applied to future soil excavation problems.

Abstract: To simulate the Rankine earth pressure theory in the finite element analysis, a frictionless rigid wall and backfill system supported by rollers can be used. Beginning from the initial at-rest pressure conditions, the wall is moved towards or away from the backfill in a series of increments, until the passive or active earth pressure condition is reached. To obtain numerical solutions, twenty-five finite isoparametric elements are used to simulate the backfill and six linear bar elements to represent the rigid retaining wall. In order to simulate the incremental displacements, bar elements with a very high stiffness are used. The effect of wall displacement can be accomplished by applying a load equal to the value of the bar stiffness times the displacement to the nodal points that connect bars and soil elements. The elastic-plastic Drucker-Prager soil model is used in this study. Two earth pressure study cases have been analyzed. The first case deals with a cohesionless soil, while the second one a cohesive soil. The obtained load-displacement curves and stress-displacement curves are presented. It is found that the earth pressures behind the retaining wall at different heights based on the numerical solutions are identical with the calculations obtained from the Rankine earth pressure theory.

Abstract: combined with walnut, wood grain, wood rough but uniform wood muscles, the stiffness of the medium density, bending strength and fracture strength is moderate, low rigidity, bending performance of steam., sapwood heartwood distinguish slightly obviously narrow wooden materials used in the field of integrated timber adhesive demand for experiment.This topic using room temperature fast curing of the modified vinyl acetate as integrated timber adhesive glue agent.And through the orthogonal test design, by changing the different pressure, time, dosage of curing agent, 9 groups of specimens was produced three factors, the determination of the compression shear strength, and an analysis to the walnut integrated timber pressure shear strength of the primary and secondary relations of influence: time st13 dosage of MDI st13 pressure.Experiments show that the optimum process conditions of walnut line, time is 2 h, pressure of 3 mpa, MDI dosage was 20%.Under the condition of the preparation of the line, good bonding and resistance to water, accord with national standard LY/T 1601-2002 to the requirement of integrated timber structure.