Applied Mechanics and Materials Vols. 716-717

Abstract: On the basis of different landform and multifarious topography in rugged mountainous area in southwest China, typical tunnel portals for single track tunnels in a new high speed railway line have been presented in the paper. The portal comprises headwall, shed tunnel, bridge abutment and its support. Portal with headwall is suitable for tunnel to resist front earth pressure on high and abrupt slope. Shed tunnel is placed in front of headwall so as to prevent rockfall; its outward part is built into a flared one. Meanwhile, the installation of bridge and its abutment are also included in the portal according to landform in the paper.

Abstract: Unsteady flow during lock filling and emptying in approach channel of double-line ship lock is more complicated than that of single line ship lock. In this paper, by a 3-D numerical model, the water fluctuation inside approach channel under different arrangement types of waterproof wall and the hydraulic characteristics such as longitudinal flow velocity and transverse flow velocity were analyzed on the basis of the 2000t second-line ship lock construction project of Zhuzhou navigation power junction in Xiangjiang River. According to the separate arrangement scheme and the completely-connected arrangement scheme of approach channel, the flow condition problem may exist in the scheme was analyzed. In order to improve the ship navigation and berthing condition, it was proposed that the waterproof wall should be set between the approach channels of the second-line ship lock.

Abstract: Two typical structures to concatenate bridge and tunnel portal for railway line on high and steep mountainous slope have been presented according to the complicated landform and ground geology in a new high speed railway line. Comparison between the two types of bridge-tunnel concatenation shows that separated structure is more superior in lessening train vibration than integrated structure. The prevention of rockfall from front slope at tunnel portal is still considered in the two structures. The concatenation types presented in the paper can be used to guide the design of bridge-tunnel concatenation in high speed railway line on complex and abrupt mountainous slope.

Abstract: For the common highway bridge strengthening works, this article divides the evaluation of bridge strengthening works into three categories layers - durability, safety and suitability, to evaluate the bridge strengthening from a technical level. Then analyzed separately for each category layer, select the parameter indices which have an important influence on each category layer to be the evaluation indicators. When evaluating the safety and suitability, the durability has been taken into consideration to amend their evaluation scores. On the basis of the obtained scores of the category layers, by using the Analytic Hierarchy Process method and the weighted average method, we can get the evaluate score of the members, components, parts entirety and the entirety of bridge successively. Proposed a kind of post-evaluation method applies to the common highway bridge reinforcement. This post-evaluation method provides theoretical references for the effect post-evaluation bridge reinforcement.

Abstract: The technology of hierarchical multiple high-pressure grouting is an effective approach to manage high and steep slope of broken rock mass. The number of grouting is one of the key parameters of this technology. By the analysis of mechanics and grouting theory, the anchoring effect mainly is affected by anchor slurry vein and the contact area with rock mass. Based on the system analysis of slurry vein development for first time and many times high-pressure grouting, the process flow for hierarchical multiple high-pressure grouting is put forward. Serve the rock permeability changes before and after grouting as an indicator measuring slurry and rock surface area, the method of determining grouting number based on the reliable probability is got. Combined with the engineering example of Shouyun Iron Mine, this paper puts forward the reliability criteria of working state of hierarchical multiple high-pressure grouting. Through the probability calculation, the best number of grouting is 4 times. The tests of permeability of rock mass and drawing force verify the accuracy of this determination method.

Abstract: At present, SMA mixture generally to the use of SBS modified asphalt, especially in the area of expressway construction in our country, but in recent years, the use of SBS modified asphalt has some problems, for example: SBS of storage stability of modified asphalt is a difficult problem, because SBS and asphalt compatibility between components of the difference, the modified agent and asphalt separation, reduces the performance of SBS modified asphalt; SBS modified asphalt in the stored procedure, the performance will decay, even if not stop stirring, decay cannot avoid, also influence the effect of the use of SBS modified asphalt.

Abstract: The concrete structures have been long-term corroded by soluble salts in the salinized soil, which was simulated by the way of concrete being soaked in multiple salts solution, then the failure law and mechanism of concrete was studied in this paper. The results show that salt crystallization happens on the exposed parts of concrete, the quality loss rate of concrete takes on the reduction-growth trend and the relative dynamic elastic modulus takes on the reduction-growth trend, the salt corrosion resistance of air entrained concrete is better than that of non-air-entrained concrete after long-term soaking in multiple salts solution. The failure mechanism of concrete is the result of interaction between the physical damage of salts crystallization and chemical erosion, but the former is much easier to implement than the latter.

Abstract: In the summer of southern cities of China, the duration of high temperature becomes longer which requires stricter temperature control and crack prevention measures for mass concrete in construction. By using finite element method for unsteady temperature field and stress field a simulation is made for a pump station built in summer. The cement hydration velocity of this engineering is so high that makes the temperature control very difficulty. Through result analysis of different cases, some optimized measures which include surface preservation and water cooling are proposed. It has an important significance for concrete structure in the same area.

Abstract: With the rise in the water level of the Three Gorges Project, accurately measuring the shear strength parameters of the Three Gorges Project shore landslide has important implications for the safety of the Three Gorges Project’s surrounding area. Due to the material of reservoir area slope is complex, are mostly loose accumulation, these loose accumulation are mainly composed by landslide deposits, eluvia material, alluvial matter, landslides, strong weathered, and material composition is soil with gravel or fragments stone, the conventional small specimens test has been impossible. Badong County has long rainy season, abundant rainfall, mudslides, landslides and other geological disasters are frequent, so measuring reservoir landslide shear strength of Badong County is particularly important. Therefore, this paper takes the gravel soil of piled crushed landslide of the third senior middle school in Badong County as the research object, through lab large-scale direct shear test to research the gravel soil strength parameters’ variation of the soil samples with different coarse soil content under different moisture conditions.

Abstract: For the drawbacks of construction design and regulation used in our country for long time, like construction rules are far behind, and the energy consumption of the construction process is higher, the energy-saving construction design model based on multi-level features is proposed. Through calculating the energy consumption with hours as units, and quantitative judgment is made, the appropriate formulas are utilized reasonably depending on the circumstances to compute energy consumption of construction, so as to obtain the energy-saving design under the corresponding conditions. This model can be adopted to calculate rational energy consumption, and circumvent, so that ultimately achieving energy saving. At the same time, the initial conditions of construction and matters requiring attention during the construction phase are integrated and discussed, as well as issues such as the weights of design value, as a whole to consider, to minimize the error between the design and construction.