Definition - What does Horizontal Alignment mean?
Horizontal alignment can be defined as the alignment of a pipe in the horizontal direction with respect to the proposed plan. Pipe alignment should not vary more than 6 inches in the horizontal direction and not more than two inches in the vertical direction.
Settlement and heave can cause these changes in alignment and contractors should ensure that these factors are minimized while undertaking trenchless methods of pipeline installation such as horizontal directional drilling (HDD), pipe jacking and auger boring.
Trenchlesspedia explains Horizontal Alignment
Horizontal alignment should be followed as per drawings and within tolerance limits. Sometimes adjustments in alignment may have to be made when unforeseen or unexpected situations such as difficult strata are encountered during drilling. Such situations should be brought to the notice of the engineers to initiate a contingency plan.
Test pits are often dug at regular intervals to verify the horizontal and vertical alignment is according to plan. If discrepancy is found, the engineer may ask for additional test pits for each test pit that shows that the pipeline is not in compliance with the plan.