The invention provides a method for constructing a directly-buried heat-preservation pipeline passing by a marshland section. The method comprises the steps that a marshland is filled with
coal gangue so that an operation face can be formed, a groove used for enabling the heat-preservation pipeline to be directly buried is dug in the operation face,
pebble replacement and filling are conducted on the part of
sludge at the bottom of the groove, and a
pebble replacement and filling layer allowing underground water to flow through is formed at the bottom of the groove through replaced and filled pebbles; the
water level at the bottom of the groove does not exceed the
pebble replacement and filling layer and a medium-coarse sand layer is laid between the pebble replacement and filling layer and the laid pipeline; an anchor block foundation
ditch is dug in the groove; after the medium-coarse sand layer is dried, the pipeline is installed in the groove, and
butt joint welding is conducted on the pipeline; an anchor block is installed in the anchor block foundation
ditch and used for fixing the pipeline placed in the groove; after
butt joint welding is accomplished, the groove is backfilled. According to the method, the problems that the pipeline bears force in the
sludge, the pipeline cannot effectively operate in a normal life cycle, the pipeline floats when water does not pass by, and the pipeline is long in construction period are solved.