Abstract:Nowadays， engineering construction tends to offshore and deep-water areas. As a result， large diameter rock-socketed inclined （RSI） pile has been widely applied in structures foundation in port and dock areas due to its better ability to withstand horizontal loads. However， because of limited construction sites and designed piles parameters etc.， the RSI piles construction is usually carried out by percussion drilling， with its rate of penetration （ROP，0.1~0.3m/h） much lower than that of cast-in-place piles by other construction methods. Based on this， a force model of punch hammer was established in this paper， to study its forced state of dropping process when it is applied to drill a large diameter RSI pile. The influence laws of hammer weight， stroke， pile inclination， and friction coefficient between the punch and steel guard were studied by single-factor and two-factor analyses respectively. According to the analyses， it is found that the hammer weight and stroke are the key factors affecting the ROP of RSI piles when the pile inclination is constant， and the influence of friction coefficient can be ignored to a certain degree.

Abstract:According to the ground conditions of the chemical wharf project in the Zhuangyuan’ao Port area of Wenzhou and special requirements of the wharf, slant rock-socketed piles with a slope of 1∶5～1∶6 were designed for the pile foundation. The construction job was successfully completed through taking very specific construction measures, such as the self-designed steel casing guide frame to control pile-hole inclination, percussion drilling with the cylindrical hollow hammer to sink the borehole, the rugby type tremie pipe to pour concrete, and so on. Pile-foundation inspection shows that the pile-foundation quality fully meets the specification. It provides valuable experiences for similar projects.

Abstract:Because of the complex composition, loose soil layers and low mechanical strength in miscellaneous fill site, pile foundation construction is difficult, especially for where being newly filled. With a case of bored cast-in-place pile constructed in miscellaneous fill of Changbai Mountain area, the impact drilling technology is selected after the analysis on the applicability of different holing methods. This paper introduces the construction process, difficulties and countermeasures as well as mud treatment, expounds the construction technology of rock-socketed piles in thick-layer miscellaneous fill site.

Abstract:According to the difficulties for rotary drilling rig in large diameter rock-socketed pile construction in hard rocks, cluster DTH hammer is matched as the solution. JSQ-Z positive circulation and JSQ-F reverse circulation cluster DTH hammers were designed, 3 kinds of construction methods and drilling tools matching scheme are presented, which makes large diameter rotary drilling in hard rocks more rapid, efficient and economical.

Abstract:The paper introduced the whole section compact-shock borehole building technology about the technological process and common accident treatment with a case of whole section compact-shock borehole building technology for large diameter inclined steel-pipe pile, the successful practice proved the wide application prospect of this technology.

Abstract:After analyse and summarize common method, base of theory of rockmass structure controlling, this paper selects quantity index which is simple to bored rock-socketed piles, establishes quantity expression, and provides quantity limit to mark off weathering zone of rockmass in bored rock-socketed piles.