# WORKS NOT APPEARING IN ESTIMATES
# HONG KONG
229. Retaining Walls and Boulders.-As a result of the deplorable collapse of the retaining wall at Po Hing Fong which involved the loss of many valuable lives and property, to which reference is made in paragraph 39 of this Report, a systematic survey of all Retaining Walls in the Colony was at once commenced.
During the year two hundred retaining walls were carefully examined and the observations obtained recorded for reference. Of these ninety-three are the property of the Government supporting Buildings, Roads, and Crown Land, and the remaining one hundred and seven privately owned supporting the properties of the owners concerned.
The difficulty of determining whether any particular retaining wall should or should not be rebuilt is greatly increased by the result disclosed by the investigation of the collapse above referred to, where a portion of the wall though well built and provided with the necessary weep-holes gave no indication of movement, the immediate cause of the fall being an upward movement of the strata below its foundation.
In one case only was early action necessary and shoring was accordingly erected without delay.
The practice of investigating cases of boulders reported to be a source of danger was continued, and in several instances, where immediate action was considered necessary, precautionary steps were taken and the boulders removed.
The following were some of the localities in which such action was taken:
(a). Crown Land above the Garage at Magazine Gap.
Several dangerous boulders were removed.
(b). Crown Land above R.B.L. 97.
Several dangerous boulders were removed and one was underpinned.
(c). Hillside along Mount Davis Road.
Several dangerous boulders were removed and one underpinned.
(d). Hillside above Conduit Road.
Examination made and one boulder removed.
In prosecuting these investigations, several officers of this Department devoted a considerable amount of time to the work.