The key points to the job, technical design, installation procedures and simulated operation involved in the task are detailed, thus introducing an installation technique for large-sized equipment, in which two cranes are simultaneously employed for the longitudinal and lateral movement of the equipment respectively.

The following assumptions are used in the numerical model:① There are only longitudinal slips on the interface of the.

The finite-sized light beam reflected from a weakly absorbing dielectric slab would experience a longitudinal displacement.

When measuring the salt solution concentration by laser speckle method,the beam transmits the solution and forms different longitudinal displacements,but speckle measuring is not sensible to the longitudinal displacement.

The longitudinal displacement and curvature variation are both described by deflection as solving the equations.

Through theoretical analysis and numerical simulations,it is proved that the lower lateral off-set,defocusing and lens focus,and the higher grating period would be advantageous,also an optimum spot radius exists which corresponds to a maximum value of coupling efficiency.