Applied Mechanics and Materials Vols. 744-746

Abstract: In order to study the bearing capacity of unimate cross-section pipe pile and setp cross-section pipe pile, a finite difference model of the pile-soil interaction is established by FLAC^3D,. The bearing behaviors of the setp cross-section pipe pile and the traditional unimate cross-section pipe pile are studied comparatively, the bearing performance influence factors of setp cross-section pipe pile is discussed. The results show that setp cross-section pipe pile can decreased the settlement relative to unimate cross-section pipe pile.There is an optimum diameter ratio in theory. For a reasonable pipe diameter ratio to setp cross-section pipe pile, on the one hand, it can effectively improve the stress behaviors of pile and reduces the pile settlement.On the other hand, it also can reduce the dosage of pile material and has good economic benefits.Under the action of the determinate pile load, the increase in length can reduce the settlement,but there is an optimal pile length, by increasing pile length to reduce the settlement of piles has little effect when the pile length exceeds the optimal length of pile.

Abstract: The highway from Mawei to Jiaou is the basic project of West transportation construction projects, "karst areas Highway Engineering Geological Survey and comprehensive evaluation technology research " , the project considering the interaction between road construction and karst environmentwith "karst environment investigation, evaluation, utilization, treatment and protection "for the macro-technology concepts , fully learn from the advanced research results at home and abroad, and actively absorb sophisticated engineering experience, through theoretical analysis, numerical simulation, model test, laboratory test, relying on engineering verification and other technical means , do the research on karst area highway construction technology .

Abstract: In the large-area soft foundation reinforcement project, the loading process is relatively complicated and the preloading load is not consistent with the service load in most cases; thus the conventional settlement curve fitting method cannot nicely predict the post-construction settlement of foundation under the service load. The back analysis method can be used to obtain the calculation parameters, so the settlement and consolidation conditions under various different loads at different time can be calculated and the foundation settlement hereby can be estimated exactly.

Abstract: To study extruding soil caused of close-mouth step cross-section pipe Pile, model experimentals of five static piling tests with two constant cross-section pipe piles and three step cross-scetion pipe piles are performed in lab respectively and some observation points are installed for heave amount and horizontal displacement of soil surface around piles before tests.Results show that penetration resistance improved linearly with increasing of length of pile in soil and there has a turning point which become more and more obviously with increasing of average diameter of step cross-section pipe pile after the pile length in soil is 70cm.Comparing with uniform cross-section pipe pile, penetration resistance per unit volume is more bigger and increases with improving of variable cross-section ratio to step cross-section pipe pile.The swelling-up amount of soil around step cross-section pipe pile increases firstly, then decreases secondly ,and increases finally. Camparing with uniform cross-section pipe pile, the maximum heaves have 51.0% and 44.6% reduce respectively to setp cross-section pipe pile and the position of largest heaves moved from 1.0d to 1.5d.Moreover, the largest horizontal displacements have 24.6% and 26.9% reduce respectively to step cros-section pipe pile and the point of largest horizontal displacement moved from 2.0d to 2.5d.

Abstract: Based on Duncan-Chang’s E-B constitutive material model, the finite element calculating model for a CFRD was established, and has obtained the stress-strain distribution and variety rule at the dam and the face slab in construction period and water store period. The calculation results show that: the stress-deformation behavior of the dam is normal, the deformation values within the acceptable range; the shear failure for the dam is almost impossible; stress concentration and tensile loading on small principal stress was exist on small range of the dam foundation covered by toe slab; the substantially change of water level has great effect on the deformation and camber of the face slabs; the faults structures in dam foundation only has affect the stress distribution of the foundation, but has weak impact of the stress and deformation of the dam body.

Abstract: The time-space change rules of the environmental effects of the analysis of excess pore water pressure dissipation have also been studied during the static sinking-pile of the pipe-pile with hole. The results show: The excess pore water pressure will be dissipated with the time extending during the static sinking-pile of the 3 kinds of pipe-pole with hole. On the condition of the same effective radius, the depth of the observation dot is bigger, the excess pore water pressure will be bigger. On the contrast to the pipe-pole without hole, to some extent, the pipe-pole with hole can reduce the maximum of excess pore water pressure, and expedite the excess pore water pressure dissipation. This results can be provided the credible base for the theory research on the pipe-pole with hole and its application.

Abstract: The reinforcement of expansive soil cutting slope has been a difficulty for the construction industry. This study selected Wanyi Expressway as the construction background and used finite difference method for the numerical simulation and design optimization of expansive soil cutting slope reinforced by sash girder anchor bolts. Calculation results show that the cutting slope ratio is closely related to the stability of the expansive soil cutting slope and that the length, set angle, and vertical spacing of the anchor bolts significantly influence the deformation of the cutting slope. The original design plan was optimized according to the calculation results, and a positive effect in plan execution was achieved. This study may serve as a reference for other similar construction designs.

Abstract: In view of the holes appearing in different areas of geo-membrane when the geo-membrane technology is applied to the unsaturated expansive soil canal slope, the VADOSE/W is used to analyze the pore-water pressure of the internal canal slope by changing the falling water level. The results show that the hole is nearer to the toe of slope, its effect on the whole seepage field is greater. The greater the rate is, the soil water content is greater.

Abstract: In the project of the fill section widening of the cantilever high retaining wall of the old embankment, the construction of the embankment widening is carried out under the condition of allowing cars to drive through. As the stability of the old embankment and the normal and safe car driving shall be guaranteed, the cantilever reinforcement high retaining wall can’t be dismantled once for all or completely during the widening process, and the conventional construction of excavating the steps for joining the new and old embankments. This paper aims to solve the defects of the conventional construction method by introducing a newly-developed construction technology of embankment widening of waterside cantilever high retaining wall, which can effectively solve the anti-floating problem of the light-weight embankment, prevent the differential deformation at the joint of the wall bottom plate and the reinforced concrete continuous slab of the cantilever retaining wall, and improve the bearing capacity of the embankment.

Abstract: The conventional subgrade slope usually adopts masonry protection. As the wall top is difficult to be provided with water proofing, the construction quality can’t be guaranteed. Thus, during the rainy seasons, rain infiltrates downward along the wall body to make the soil body behind the wall to be soaked to settle, which leads to subsurface erosion and finally damages the facing wall and the slope. The masonry retaining wall needs to consume a large amount of stones, and the wall surface can’t be planted, which doesn’t conform to the national requirements on energy-saving and consumption-reducing and ecological highway development. This paper innovates on the conventional retaining wall technology and introduces a newly-researched construction technology of three-dimensional reinforced rigid-flexible composite ecological retaining wall, which greatly improves the integrity and anti-deformation capability of the soil body behind the wall, reduces the subsidiary stress on the foundation base, improves the bearing capacity of the foundation, and the anti-sliding and anti-overturning stability of the retaining wall.