Based on analyzing the modulation and demodulation principle for QDPSK signal, an improved modulation solution for QDPSK signal based on FPGA is proposed.

The reason for the appearance of internal friction in tubular piles is that the relative displacement or its trend exists between the soil core and piles.

A group of equations for lateral friction of single pile and relative displacement between pile and soil are established and calculated the bearing capacity of single pile.

<Abstrcat>Considering non-linear of soil around pile, this article analyzes and calculates the effect of the cement substitute for mud on the side-friction character, and then explains the phenomena of the side-friction increase of the cement substitute section after grouting and the relative displacement increase of the needed soil around the pile.

The relative slip on the interface of prestressed steel-concrete composite beam appears to a certainty with the external loading,the internal force of tendon will increase along with external loading continuously,and the intemal force increment will affect to the interface slip too.

With elastic theory method of single pile as base,the calculation model considering relative slip caused by pile soil interface was built.

Assuming that the longitudinal displacement of composite steel-concrete beam with lightweight aggregate flange follows cubic parabola in the transverse direction,with interface relative slippage function for composite beam as unknown function,the control differential equation can be established based on minimum potential energy principle for solving theoretical distribution of l.

In this paper the relative slippage, connectors stiffness and shrinkage & creep are considered.

Both the softening effect of soils around pile during vibration and slippage along the pile-soil interface are taken into account.