Advanced Materials Research Vols. 838-841

Abstract: Through the study of the frost injury mechanism and characteristics of concrete, the main factors that affect the frost resistance of concrete are described, and put forward measures to improve the frost resistance of concrete performance.

Abstract: Numerical simulations of effects of confining pressure on occurrence of rock lateral cracks were performed by using the numerical analysis software. The results indicate that the rock tends to have median cracks with the increasing of penetration under no confining pressure, while the rock tends to have lateral cracks with the increasing of penetration under confining pressure. The relative position of lateral crack initiation is dependent on the confining pressure when loading, which is independent of the penetration. The greater the confining pressure, the closer the lateral crack location to the rock surface. With the increasing of penetration and confining pressure, the lateral crack direction is towards to the direction parallel to the rock surface.

Abstract: The bearing capacity characteristics and side friction characters of post-grouting pile were studied in the static load test which included two piles with post-grouting or not. When the pile head settlements were same, the loads applied on the pile top were used to analyze the bearing properties of post-grouting pile. We got the ultimate side friction of post-grouting pile after fitting test curves of relations between friction resistance and displacement. The tests indicate that both the bearing capacity characteristics and side friction of post-grouting pile are increased in various degrees.

Abstract: In the northeast of China,the research of subway foundation pit is still infancy,which needs enriching. This paper relies on the deep foundation pit engineering of Xiashengou Subway Station in Shenyang. Through the analysis of deformation foundation pits to study deformation characteristics.Through the monitoring data,we can know that combined the bored and steel support the deformation of the retaining structure and the ground surface subsidence can be well controlled.The deformation of the envelope and the surface has a strong time effect and increases with time,in the excavation stage,pile deformation presented randomness. In the excavation stage, pile deformation presented randomness.When the excavation completed 45 days,from the top of the pile to the pile at 13m depth,the lateral volume is almost equal, and thus down to the pile end the lateral volume gradually becomes zero.

Abstract: The channel sand in PI3132 units of A area in Daqing oilfield is meandering river sand body. Although more than 90 percent of it is watering out, the serious heterogeneity in layers make it possible that there are plenty of remaining reserves in unwashed or low-washed segments in water flooded layers. All these two kinds of remaining oil are the main potential tapping objectives in later period of oilfield development.The writer deeply analyzed the point bar sand body of the meandering river, established the recognizing method of the abandoned channel and the lateral accretion body of point bar, understood the remaining oil distribution in the washed segments and unwashed segments of the thick oil layers. By implementing the Personalized treatments for individual wells,such as super-short radius horizontal wells drilling,waterflood depth profile controlling,cyclic injecting and producing, etc, the point bar sand body potential tapping technology for different formation cause has been established. And this has essential meaning to direct the oilfield development.

Abstract: Through indoor artificial rainfall test on the model slope of the laterite, the soil tests on samples of different parts of the model slope of laterite were carried out in the end of rainfall. According to the test results, the changes of the water content, the grain composition and the shear strength of the laterite in the model slope were analysed. The results showed that the effect of rainfall caused the water content of the laterite in the model slope to increase, and the altitude of the model slope was lower, the water content of the laterite in the model slope was higher. The effect of rainfall led to the density of the laterite in the model slope to decrease gradually when the altitude of the model slope was lower gradually. The grain composition exhibited that the silt content was increased and the clay content was reduced with the decrease of the model slope altitude. Based on analysing the variation of the water content, density and grain composition in the laterite of the model slope under the effect of rainfall, the changes of the shear strength of the laterite in the model slope were studied, further the changes of the cementatory characteristics of the laterite in the model slope were analysed under the effect of rainfall.

Abstract: This paper mainly introduces the characteristic of collapsible loess high fill roadbed, the observation method of collapsible loess high fill embankment settlement and measures need to be taken in construction and observation process of collapsible loess high fill embankment, through the settlement observation can be found in a timely fashion in roadbed construction process the settlement of foundation and roadbed soil. Thus it is concluded that the influence of construction process, construction method and filled soil type on the roadbed settlement. And sum up the settlement law.

Abstract: The underground powerhouse of Houziyan hydropower station has some typical characteristics such as high strata stress, large span and high sidewalls. In this paper, numerical simulation of continuous excavation and support of the underground caverns was performed using the Fast Lagrangian Analysis of Continuum method (FLAC^3D). Then, the distribution characteristic of the deformation field, stress field and plastic zones was analyzed based on the numerical calculation results. In addition, the distribution of stress was compared with microseismic events. It shows that stress concentration can cause micro-seismic events regional aggregation.

Abstract: This document introduces basic principles of transmission in underground rock of ground penetrating radar (GPR) . Then an in-depth analysis on key parameters affecting the detection has been done, and detection resolution of radar are researched. By the technology, exploration experiments on Karst,little faults in coal seam and concealed metal drill pipe have been carried out. The results show that ground penetrating radar technology is a fast, efficient and intuitive geophysical detection technology, which provides a reliable technical means of solving the detection with close range and high precision.

Abstract: The right bank underground powerhouse of Houziyan hydropower station is a typical deep-buried type with high geostress and complicated geological conditions. To monitor and analyze the stability of surrounding rock mass during continuous excavation of the powerhouse excavation and locate the potential failure zones, an ESG (Engineering Seismology Group) microseismic monitoring system manufactured in Canada was installed in April, 2013. The wave velocity of the monitoring system was determined through fixed blasting tests. And the average location error is the minimum while P-wave velocity is 5700m/s, less than 10m and meeting the system request. By combining the temporal and spatial distribution regularity of microseimic events with field excavation, micro-crack clusters and potential instability zones were identified and delineated. The results will provide a reference for later excavations and supports of the underground powerhouse. Furthermore, a new monitoring method can also be supplied for the stability analysis of surrounding rock mass in deep-buried underground powerhouses.