No abstract

To determine the ultimate load capacity of drilled shaft socketed into rock under axial compression loading, it is necessary to predict both the ultimate side shear resistance and the base resistance based on field load test or/ and laboratory tests. In geotechnical engineering there are several methods proposed the relationship between rock properties (the unconfined compressive strength) and the ultimate side shears resistance and base resistance. This paper presents the review of design methods of ultimate side shear and base resistance for rock-socketed pile. These empirical functions depend on the socket type and the range of the unconfined compressive strength of rock.

To study the working behavior of a rigid pile composite foundation of high-rise buildings, an in-situ loading test and stress test on piles and soil were carried out. According to the test results, the stress distributions and variations, load transferring characteristics, and stress distributions of piles were analyzed. The results showed that the piles with the formation of non-soil compaction technology can consolidate soil among piles. When the load level was greater than 240 kPa, a better consolidation effect can be obtained. The development negative friction at the top of piles was relevant to the load level. The adjustment effect of cushion on the composite foundation was mainly embodied before the load level reached the characteristic bearing capacity of the composite foundation. Under vertical load, the stress distributions along the internal and external sides of pile shaft were different and the loading plate would bring influence to stress distributions of the pile shaft. The influence range was from the middle to the top of the pile. Based on the test results, it is recommended to reduce the evaluation standard of the bearing capacity determined in the pressing plate test. The results can provide a reference for similar engineering.

The in-situ tests of horizontal bearing capacity on inclined steel pipe piles were conducted in the sea near Shanghai. Based on the field experiment with the lateral unidirectional and single cycle loading test method, this document presents the horizontal displacement and bearing capacity on the inclined steel pipe piles with negative and positive inclination angles. And the horizontal bearing capacity of the steel pipe pile with positive inclination angle is larger than the one with negative inclination angle. And the tests results can be provided for similar engineering reference.

Regarding the cylinder piston ring friction pair system as the object , put forward a new numerical simulation method to study the thermal effect mechanism of single pulse interval laser micro texturing. By means of numerical simulation and experimental verification, analysis the variation of laser pulse frequency and laser power on the 45# steel surface micro cavity morphology. The simulation and experimental results show that along with the increase of laser pulse number, the depth of micro cavity increases, the recasting phenomenon of molten metal is obvious, and the machined surface quality decreases. At the same condition, the micro cavity depth simulation results and experimental results are basically the same trend; the maximum error is less than 8%, which proves the feasibility and validity of the numerical simulation method.