Applied Mechanics and Materials Vols. 744-746

Abstract: Parameter analyses in the constitutive model determine the precision of numerical results. Cam-clay model is the first elasto-plastic model in the world and widely used in the practical engineering. SYS Cam-clay model is proposed based on Cam-clay model by incorporating the concept of overconsolidation, soil structure and anisotropy. There are two groups of parameters in this model, elasto-plastic parameters that are exactly same as those in Cam-clay model and evolutional parameters that decide the variation of overconsolidation, soil structure and anisotropy. The detailed process to determine the parameters is introduced step by step.

Abstract: Soil arch plays an important role in the landslides reinforced by stabilizing piles . A method was presented to determine the range of soil arching ring. The method proposed was achieved by finite element program and the stress distribution of soil arch with different landslide thrust was analyzed. The results show that the thickness of soil arching ring is variable. The mid-span section of soil arching ring is the minimum. The arch ring becomes thicker from the mid-span axis to the arch feet. With the increase of landslide thrust, the soil arching ring becomes thicker and thicker. At last ,the monitoring data of a model test is studied and the results are consistent with that of numerical simulation.

Abstract: This paper presents a numerical study that performs the stability of slopes on bedrock reinforced with single pile row at different locations. The slope is formed of top sliding soil layer that underlies over rock. The numerical analysis has been implemented by employing the three dimensional analysis using FLAC3D. The results indicate that as the pile location is moved towards the slope crest the displacement increases.In the single row of pile application, the factor of safety reached its maximum value when the pile located at the top middle of the slope. Considering the failure mode the results has conclude three failure modes; above, in front, and through the pile according to the location of the pile. Failure mode is also affected by socketed length of pile in bedrock layer. It is believed that the findings of this study contribute to the engineers performing slope stability analysis in practice.

Abstract: Bases on the project of typical natural coarse saline soil area ,Startis from the saline soil salt expansion characteristics of seven cycles of freeze-thaw cycling test and saline soil subgrade model test ,concluses not only the oil can make roadbed fillers for highway and first-class highway directily , but provides experiences for saline land area of natural coarse particles of high highway designs and construction engineering. Meanwhile, this paper also provides reference experiences for the design and construction of high level road engineering at natural coarse saline soil regions.

Abstract: The experiments were carried out on the remolded soil to study the change law of the soil properties with the numbers of freezing and thawing cycles. It aims at simulating the effect of natural environmental factors on the mechanical performances artificial filling roadbed in Songbei region. After the soil sample was compacted in the optimum moisture content, and undergone limited numbers of freezing and thawing cycles, physical and mechanical properties were measured respectively. The experimental results indicated distinct change trend on physical and mechanical properties of soil after limited numbers of freeze-thaw cycle to confirm that the fillings was susceptible of temperature and moisture in this region.

Abstract: Expansive soil of Nanyang Province in this experiment was as the research object and the different lime-mixed rates and basalt fiber-mixed rates on the strength characteristics of expansive soil were studied. The test results show that the maximum dry density and plasticity index of reinforced expansive soil were decreased along with the increased lime-mixed rates and the optimum water content was increased in the wake of the increased lime-mixed rates under the same compaction effort; unconfined compressive strength would be a peak along with the increased lime-mixed rates, ductility of reinforced expansive soil was enhanced by the basalt fiber; expansibility of reinforced expansive soil was slashed by lime and basalt fiber which was the dominant factor.

Abstract: Cohesive soils of the mixed marine and terrestrial sediment are deposited along the north side of the Yangtze River estuary of China. The natural deposit has poor physical properties, with natural water content close to or greater than the liquid limit and the void ratio close to or greater than one. These properties are similar to those of natural soft marine clays, while the former has much higher in-situ shear strength and sensitivity. To investigate the reason for the abnormal combination between the poor physical properties and the relatively good mechanical characteristics, a series of field and laboratory tests were performed on the natural mixed deposit. The results of oedometer tests and corresponding micro-structural tests under different consolidation stresses indicate that the natural mixed deposit is normally consolidated and are structured. There is a good uniformity between micro-structural change and macro-mechanical properties. It is found that the existence of structure is an essential factor, which causes the good mechanical behavior of the natural mixed deposit. The unique sedimentary environment and depositional texture of the natural cohesive soils are the direct reason that has resulted in the abnormal combination between the bad physical indexes and good mechanical characteristics.

Abstract: Expressway construction in mined-out area is faced with some challenges, such as differential settlement and excessive deformation. This paper presents a case study of grouting improvement in a mined-out area under Tangshan-Tianjin expressway, China. The geological conditions in the mined-out area and the mechanisms of surface subsidence are described. A detailed grouting treatment scheme is planned and carried out to reinforce the rock masses. Technical requirements for grouting are described to ensure the reinforcement effect. Verification of the reinforcement effect is carried out using several techniques such as packer test and core drilling method. The results show that the proposed grouting scheme achieves desired effects.

Abstract: For computing the stress and strain of embankment dams, FEM is employed. Two reservoir filling paths which are constructing filling and completed filling are considered to affect the computing results. It is proved that constructing filling path can enhance the stress of embankment dams. So constructing filling path can take from the hydraulic fracturing of core wall. In addition, constructing filling path can decrease the amount of settlement, and can control the displacement of dam shoulders. In a word, constructing filling path is prior to completed filling path.

Abstract: According to the mechanics characteristics of inclined plane foundations in transmission line project, rotary theories of spatial coordinate system were used. Load conversion method on inclined plane foundation is analyzed and obtained to get normal section bearing capacity of the column. Meanwhile, the derivation steps and calculation formulas are shown.