The nonlinear T-Z curve of rigid group piles is derived from the increasing settlement of the pile shaft induced by the interaction ofpile-soil-pile system.

Problem on the bearing capacity of cast-in-place pile influenced by the deposit at pile end and the mud hanged on pile shaft can be solved by the technique with the post grouting.

Problem on the bearing capacity of cast-in-place pile influenced by the deposit at pile end and the mud hanged on pile shaft can be solved by the technique with the post grouting.

The test results show that the pile shaft of deep mixing piles is continuous and hard, the SPT blow count N63.5 is 21. 6 at 10 day ages, and the unconfined compression strength quis 2. 5MPa at 150 day ages.

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.

Using the stress test results with sliding micrometer, the author analyze the varied feature of pile shaft compression, the distribution of shaft axial force, the impact of lateral friction resistance of the super-longhole pile and the influence factors;

On the basis of engineering example analysis, the cause of unevenness in quality of dry jet mixing pile shaft was detailedly analysed and explained from reinforcement mechanism, construction technology and quality test respectively.

Combining pile capacity with integrity test,the paper evaluates thoroughly the qulity of pile shaft. Some suggestions are presented for the application of powdered jet pile composite foundation.

Combining pile capacity with integrity test, the paper evaluates thoroughly the qulity of pile shaft. Some suggestions are presented for the application of powdered jet pile composite foundation.

The method can be employed to obtain various distributive curves of axial force, settlements and skin friction along the pile shaft with the changes of active depth, vertical movements of the surface and loads of pile-top.

The employed method can contribute to determining the greatest tension along pile shaft resulting from expansive soils swelling and provide reliable bases for engineering design.

The soil around the pile shaft is assumed to be rigid-plastic, while that under the pile-tip is assumed to be ideally elastoplastic.

Well, the presumption is true for the pile shaft, but not the pile toe.

The pile toe behavior is influenced by that set-up after installation loads the pile shaft and transfers load to the pile toe.

From pile load-transfer analyses, it is known that the sequence of mobilization of pile shaft skin friction and that of pile point resistance are quite different. Thus determining single-pile bearing capacity with a single safety factor K is rather ambiguous, two partial safety factors, namely, one for shaft skin friction and another for point resistance, should be used instead.In this paper the load transfer of loading tests on five model piles and seventeen prototype driven and...

From pile load-transfer analyses, it is known that the sequence of mobilization of pile shaft skin friction and that of pile point resistance are quite different. Thus determining single-pile bearing capacity with a single safety factor K is rather ambiguous, two partial safety factors, namely, one for shaft skin friction and another for point resistance, should be used instead.In this paper the load transfer of loading tests on five model piles and seventeen prototype driven and bored piles is analyzed. For these piles, curves of safety-factors Kf and Kb as functions of the degree of mobilization of point resistance a are obtained, which well represent load-transfer behavior. From the test data the Kf and Kb -(s/d)curves are also obtained, where s/d is relative settlement of the pile; from these, for K=2,ranges of Kf -and Kb -values and corresponding s/d values have been obtained, and it is hoped that these may prove to be of some value in practical design work.

Bearing capacity of pile is usually determined by field test. The results of few test piles are conventionally regarded as a design basis for all other piles in the same site. However, the practical experience of pile test shows that quite a large deviation of the actual bearing capacity of piles exists. Therefore, it is worth while to discuss whether the bearing capacities of few test piles can be directly used as a design value, and if so, how about its reliability?Based on the test data of bearing capacity...

Bearing capacity of pile is usually determined by field test. The results of few test piles are conventionally regarded as a design basis for all other piles in the same site. However, the practical experience of pile test shows that quite a large deviation of the actual bearing capacity of piles exists. Therefore, it is worth while to discuss whether the bearing capacities of few test piles can be directly used as a design value, and if so, how about its reliability?Based on the test data of bearing capacity of 71 cast-in-place piles (38 piles with a diameter of 0.8m and 33 with a diameter of 0.6m ), the following conclusions have been drawn:1. It is evident that the test data of pile load tests scatter over a wide range and the maximum bearing capacity can be twice as large as the minimum one.The coefficient of variation (C_v=σ/(?)_α) is more than 0.13.2. The reasons that cause dispersion of bearing capacity values are: non-homogeneity of soil at same construction site; the differences in real pile length and diameter; the quality of casting concrete; the thickness of sludge directly beneath the pile bottom as well as the verticality of pile shaft. Thus, the dispersion of bearing capacity is closely related to the construction technology, construction procedure and construction quality as well.3. As stated above, the real value of pile bearing capacity is a random variable, therefore it shoud be handled by means of mathematical statistics.The frequency distribution of bearing capacity of tested piles can be regarded as a normal one.Finally, the writers suggest that the choice of the design bearing capacity should be based on guarantee ratio(or probability)according to the importance of engineering projects and the working conditions of piles(e.g. the number of piles under a pile cap).It is better to have a big sample for bearing capacity statistics, so it has to increase the number of load test piles.An illustration has been also presented in the paper.

By using Rayleigh method, we propose a formula to calculate the coefficients of resistance of the soil around the pile shaft with the measured frequencies of the piles. The calculated results of these coefficients as well as the bending moments along piles and the displacements of pile heads derived from the coefficients agree very well with the data obtained from a large number of model tests for the comparision of static and dynamic behaviours.