| Comparing with other forms of base construction, socketed piles are more widely used in civil engineering because of their higher bearing capacity, littler settlement. But the research on its bearing mechanism and work properties is insufficient. especially on the bearing properties of the large-diameter and medium-long socketed piles in mudstone foundation.The Xigeda-mudstone is widely distributed in Xichang and Panzhihua regions of Sichuan province. It's a kind of dead soft-rock with some special characteristics of muddiness, softenness, dehydrate and rift etc when it meet water. However, the articles about the socketed piles in this stratum had not been discovered. And the clear and complete calculation methods of the piles in soft-rock in the standards have not yet been found.On the basis of Testing Study on Bearing Properties of Bored Pile in Xigeda-mudstone in Xichang - Panzhihua Expressway Project, this paper works in three aspects. One is the research on the vertical bearing characteristics of piles. In this section the author analyses the rules of the pile ultimate tip resistance and the shaft friction resistance distribution and their exertion of cast-in-place socketed piles instrumented with strainometers in soft muddy rock. The second aspect of the paper is the analysis on the current rock pile vertical bearing capacity in the four standards GB50007-2002, TB 10002.5-99, JTJ024-85 and JGJ94-94, then the design method with correlated formula of socketed piles in Xigeda-mudstone is given. At the end of this paper, based on the research of pressure grouting technique in recent years, and combined with in-site test result, this paper puts forward the design and calculation method to grouted pile in Xigeda-mudstone and the principle of choosing grouting parameters, which provides experiences for applying this technique and further studying. And reference to reasonable selection of pile type and construction in such rock is also presented.
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