Burying earth pressure cell under the base of WJP to measure pile end stress,and doing the loading test in 28d,pile strength indexes in different conservation temperature and soil horizon can be obtained.
The testing parameters influenced by the relative position between transmitter and vibrational excitation point are investigated. The relation between pile strength and the velocity of elastic wave is studied. This work opens up a new field of the application of the low strain dynamic testing and accumulates the experience of the piles testing.
Through practical application of dry jet mixing pile in west extension line,the author illustrates the factors to control pile strength,foundation settlement and bearing capacity of composite foundation in its foundation treatment engineering from design and construction,and shows by practices that dry jet mixing pile has the advantages of economy,environmental protection and construction convenience,has been extensively utilized in foundation treatment, and has gained well engineering effect and social benefits.
In accordance with ground upheaval caused by the returned cemented soil when the highly saturated soft soil is treated with deep mixing pile, the paper analyses pile strength influenced by the quantity of upheaval, enumerates the difference of the actual and required mixing ratio of cement.
The reinforcement principle of cement and soft soil under mechanical mixing is analyzed. From four aspects: stratum,time,material and construction the factors influencing the strength of deep-mixing pile are discussed; at the same time corresponding methods are proposed to increase the pile strength and bearing capacity of single pile.
By analyzing the influences of such factors as flow-up of grout, irrational remixing depth, uniformity of soil-mixing and improperly selected additives on pile shaft strength of deep-mixing piles and bearing capacity of single pile, the paper discusses the measures of improving pile shaft strength and bearing capacity of single deep-mixing pile.
However, for the insufficiency of the knowledge of how the factors and surroundings affect the quality of WJP (such as the ground temperature and soil properties),on the work field, the construction of filling soil is usually carried out before the WJP achieves its qualified strength, and this leads to series of accidents, such as the settlement of embankment 、dehiscence of pavement, which is lead by lack of the bearing capacity.
This thesis analyze some influencing factors, such as shape of pile, soil on the end and side of pile, concrete strength of pile, and soil in the pile. It provided reference to application of this pile in harbor engineering.
Dry powder jump piles are widely used in soft soil areas as a method of consolidating soil.Samples of cemont-soil are tested for their mechanical characters, By comparing with the conditions of the field, the auther of the paper gives the standard value of dry powder jump pile strength.The results can be used for reference by reaseachers and designers.
With limit equilibrium theory, the sample's compressive strength which is reinforced by geogrid is analyzed. The formulas about its capacity and the angle of sliding surface are deduced under the conditions of geogrid's tension fracture and cohesive failure on the interface between geogrid and soil. They are checked by using datum which are obtained by experiments. The influcnce on column's strength which is made by the number of geogrid layers and the embedding depthof geogrid is also expounded.