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Summary of Findings of Landslide Investigation

Slope Distress at Queen's Hill, Burma Lines Camp, Fanling

Basic Data

Material: Colluvium / Decomposed Volcanic Rocks
Feature Affected: Natural Hillside above Cut Slope No. 3SW-B/C12
Volume: > 1,500 m3 Displaced
Report Reference: LSR 10/99
Photo of section
Section Location plan

Description

This incident involved extensive distress on a natural hillside.  The distress predominantly involved slope movement, tension cracking and localised detachment.  Some of the distress could be identified from aerial photographs dating back to 1924.  The hillside instability was not identified during the detailed study of the cut slope at the toe of the hillside under the Landslip Preventive Measures (LPM) Programme in 1997.  Not all the relevant aerial photographs were examined during the detailed study.

The identification of distress on the hillside has necessitated the evacuation of a number of dwellings at the toe of the hillside.  Further vegetation clearance during the landslide study revealed more extensive distress which resulted in more dwellings having to be evacuated.

There is evidence over parts of the hillside that progressive ground movement and deterioration of the ground condition with time (e.g. cracking and opening up of the ground) could develop into more mobile failures.

Observations

The following observations can be made from this landslide incident :

  • The design engineer should be charged with the responsibility of ensuring that a comprehensive API report is prepared for the general area of the subject site.  Detailed inspections of the site and its surrounding areas are also necessary to supplement the API.
  • Significant natural terrain landslides, particularly those close to developments, should be studied to improve the understanding of the diverse range of hillside instability problems.