Researching The Technologies And Bearing Value Of Bored Cast-in-place Pile Pressed Mixture Of Cement And Slag Power

With the arising of high-level buildings and large-scale buildings, there is a more requirement for the resistance of single pile foundation of bored cast-in-place pile. In order to meet this requirement, increasing length and diameter is adopted in practical engineering, but it also brings about some disadvantages, such as difficulties to construct and to dispose rubbish. Consequently, the mud jacking technology of bored cast-in-place pile at end of pile comes into being and is applied to in engineering practice. It is a construction method to increase greatly bearing value, which improving or eliminating mud sheets and bored-bottom dregs, and renewing and enhancing the strength of disturbed and softened soil, and conquering and compensating the lack of the strength of the pile. But for normal bored cast-in-pile, neat cement is used in practice, it increases amount of materials and cost. Slag power, which is a by-production and waste of industry, can be applied to super performance concrete, and can also take for activated raw materials. Accordingly, for the purpose of expanding applied-field of it, slag power can be used to replace partial cement in cement paste, in post mud-jacking construction of bored cast-in-place pile. The research of this project, can realize three goals. Firstly, the cost of a single pile will be dramatically reduced, since the price of slag power is less than that of cement; secondly, this technique can take advantage of industrial waste, and settle responding problems on environmental protection, and accord to the ideology stratagem of sustainable development. Finally, that is the most important, this project will provide theoretical data to support for the usage of this technique, thereby economic and social benefits will be come truth. The main works in this paper are list as follows:(1) Analyzing the mechanism and effect of post mud-jacking in bored cast-in-place pile to determine the construction technology;(2) Under the same conditions measuring separately flow ability and 3 7and 28 day's strength for different amount of power to define the most appropriate percent of power;(3) Calculation method and main points of technology parameter of mud-jacking are researched.(4) Compare the technologies for slag power grout and for neat cement paste used in bored cast-in-place pile.(5) By static load tests, analysis and compare the bearing values of post mud-jacking with neat cement and mixture of cement and slag power; By mechanics analysis for single pile, determine the ultimate strength, lateral shear and axial force of the bored cast-in-place pile with slag power. Prove the practice of this technology by the agreement of the results of the calculation and those of the tests.(6) Making economical evaluation for the technique to prove it can meets design demands, construction conveniences and reliable mechanics behavior, and reduce the constraction cost.