Advanced Materials Research Vols. 594-597

Abstract: Primary and secondary consolidation concur in the primary consolidation stage. Especially for the dredger fill with high moisture content, the coupling effect of primary and secondary consolidation was very obvious. Analysis on the secondary consolidation properties during primary consolidation is great significant to reveal the consolidation mechanism and identify the settlement calculation method. Therefore one dimensional consolidation tests were conducted with the dredger fill clay of Wenzhou over liquid limit. The tests were focused on the influence of different vertical loading and back pressure condition on soil’s secondary consolidation properties. The research showed that the secondary consolidation of dredger fill of in high moisture content was very obvious under the primary consolidation stage. The final consolidation pressure level was higher, the vertical deformation was larger at the same effective stress level. Through the consolidation tests with different back pressure levels, it further verified high pore pressure potential promoted the development of secondary consolidation. Further more, when the final consolidation pressure was a constant value, the total settlement of primary and secondary consolidation basically unchanged. So high pore pressure promoted the occurrence of secondary consolidation, but reduced and sped up the development of primary consolidation.

Abstract: Using the RMT-150C rock mechanics test system, the instantaneous triaxial compression tests for muddy siltstone were carried out under different confining pressures, and the instantaneous mechanical properties of soft rock were obtained. The results show that the strength parameters of sample have a positive linear relation with the confining pressure, and the sensitivity of peak strength on the confining pressure is higher than that of residual strength. The elastic and deformation modulus of sample linearly increase with the confining pressure going up, and the elastic modulus is more sensitive to the confining pressure. The soft rock sample shows typical ductility failure characteristic, while the damage characteristic is mainly shear failure and the shear failure angle linearly decreases with the confining pressure going up.

Abstract: Although anti-slide pile take a key position in slope-treating measures, the method of designing is far from perfect. The methods used in actual projects are based on the rigid body limit equilibrium methods. There is a tendency to using numerical methods in the progress of pile-designing. The safety factor of landslide is calculated according to shear strength reduction theory in the numerical simulation software. Using the shearing forces on pile and the safety factor can ascertain the position of anti-slide piles, the area and distance of piles. For numerical simulation can well perform the simulation slope moving and the load on piles and can give a more reasonable designing.

Abstract: The branch well G8-33-H1Z is the first fishbone horizontal well of Daqing. The fishbone horizontal well is one type of the branch horizontal wells, which drilling again two or more branch holes in the horizontal section of the horizontal well. This well lies in G21 block where is near to the west of Daqing oilfield Changyuan area and the northeast of G20 of the north Gaotaizi oilfield. The purpose of the drilling is using branch horizontal well to control more areal reserves and increasing drainable area to improve well production. This technique can improve the economic benefit of oilfield development, which saves drilling investment, makes full use of the upper borehole to improve the comprehensive exploitation degree of the reservoir and achieves highly efficient development using less well. This well has two horizontal branches, and puts ‘trunk-branch-trunk-branch’ into effect while drilling. The first branch designed horizontal length 150m. The second branch designed horizontal length 150m. This paper introduced the tracing with drilling process of Daqing first fishbone horizontal well, and also described the complex situations and the treatment methods while drilling wellbore trajectory and constructing well and the development effect. Finally some suggestions were put forward about tracing with drilling in fishbone horizontal well.

Abstract: In this article, we define rock structural planes caused by mineral orientation and layering distribution of some rock ingredients which is different from both rock mass scale structural planes and micro structural plane at crystal scale, as rock mesoscopic structural plane, and the rock anisotropy caused by the existence of these structural planes as rock mesoscopic anisotropy. Rock mesoscopic scale anisotropy index is introduced and its simple but efficient testing method is suggested. With the rock mesoscopic anisotropy index, the degree of rock mesoscopic anisotropy can be quantified easily and the process in simplified.

Abstract: Now, with the large-scale of various projects constructed, a lot of the original vegetation were destroyed and formed a large area of bare slope. The existence of slopes increased the occurrent intensity of soil erosion, landslides and debris flow, and also caused local ecological disasters of the deterioration of the microclimate and the destruction of the biological chain. Based on this situation, this article discussed the reinforced soil reinforcement of shallow fine roots and deep rough roots, and generalized comprehensively the root factors on the impact of the reinforced soil, and explored the lack of research and development trends of vegetation slope protection.

Abstract: Based on the introduction of mechanism of ground grouting to reinforce shaft lining in detail, the paper analyzes the weakening effect of additional stress of shaft lining from ground grouting. According to the monitoring results of deformation of ground surface, shaft lining strain, and grouting curtain after grouting, the grouting activity makes the surface uplift of about50-80mm, shaft lining vertical strain release about 220με, mortar curtain average thickness near 8.2m, and the mechanical properties of soil are improved obviously.As a result of ground grouting effectively weaken the additional force has been accumulation for long time of shaft lining, and it can achieve the purpose of prevention and treatment the rupture of shaft lining. Ground grouting is a feasible means to control shaft lining.

Abstract: The 3D model of terrain, which includes goafs, is built by use of terrain generator from MIDAS GTS. The method is developed that the model is stress analyzed by FEM (finite-element method). The following cases are considered: rock weight, loose rock and Heavy Equipment on step surface. Finally, used to the field datum from Luo’yang Molybdenum Co., Ltd., modeling and stress analyzing are finished by the software of MIDAS GTS. The result indicates that the method could provide scientific basis for Safety and Management to open-pit with Underground mined-out area.

Abstract: The compressibility of contaminated soil was analyzed through the consolidation test. The results show that, with increasing of the acid concentration, the soil compression is increased. The compression of soil contaminated by alkaline is larger than the soil contaminated by acid. The temperature at beginning section plays catalytic effect on soil structural damage, and the amount of compression of the soil is significantly increased with an increase of temperature. When temperature is increased to a certain value, the amount of compression decreases conversely, this may the cohesion between the soil particles is strengthened. However, with the further rise in temperature, the soil structure shows irreversible damage.

Abstract: The anchor which added a elastic-flexible deformable body on the common anchor will be form a new type anchor, it is called the elastic-flexible anchor. With the help of FLAC3D 3.0, we compared the numerical simulation analysis results between the common anchor and the elastic-flexible anchor. we obtained that, the elastic-flexible anchor has the higher bearing capacity and more excellent anti-deformation performance, this mainly due to the elastic-flexible deformable body which has the buffering effect of the stress and deformation. The results confirmed the elastic-flexible anchor especially applied to the support structure with the requirements of large deformation and dynamic load, and worth popularizing in the anchor retaining wall engineering.