Wednesday, April 1, 2009
Report from Resident Manager to JMC on Hill Slope Inspection by DBKL Technical Department
Dear All JMC members & advisor,
The site visit had been conducted by the slope unit today.
The main purpose for the site visit is (1) to provide comment on the water seepage problem which occurred at Level P4 a few months ago; (2) to provide advice on the maintenance of the adjoining slope next to this building; and (3) to look into soil stability test for the slope.
The feed back from the Slope Unit on:-
(1) Water seepage problem at Level P4
According to the officers, the area of the car park at Level P4 where the water seepage once occurred is near to the portion of the original slope that had been cut off during the construction. Thus, the construction of the wall of the car park had cut off at the part of the water table of the original slope. Water from the water table of the slope is at high pressure especially under the floor slab and behind the concrete wall of the Level P4 car park which is near to the earth. Hence, water due to high pressure will find its way through capillaries, crack lines into Level P4 car park.
The advice is that during construction period, the developer should provide for sufficient and proper water pressure protection for these areas to disallow water from seeping through.
We have informed them with regards to the works done by the developer to resolve the problem by means of constructing additional drainage way for water on the floor slab and covering the water seepage area with cement, and thereafter the water seepage problem stops. According to their explanation, the works is considered as fine and effective since the water stops seeping through after they carried out the work. In addition, they noted that no seepage of water from the wall near to the slope and thus, they mentioned that the situation of the seepage problem is fine.
(2) Maintenance of adjoining slope next to the building
According the the officers, the Slope Unit will look into the maintenance issue of slope belonging to the local authority, while for the portion of slope which belongs to the development, the Management will have to look into it. Our request to them is that proper maintenance be carried out for the slope belonging to the local authority. However, we will look into the boundary plan and send them a copy of the same for their record and further action.
On the maintenance of the slope, as the slope facing the building had been granited, they have informed that it is important to ensure that no major cracks occur on the granite which is meant to support the soil. For this purpose, we have to check and remove trees/plants with huge trunks from the granited slope in order not to have cracks caused on the granite due to these big tree trunks, that will lead to soil erosion. However, some vegetation on the slope will be good for the soil of the slope.
The seep holes found on the granited slope allows water to flow out upon reaching certain level of the water table in the slope. The occassion of water flowing out from these holes depend on the volumn of water inside the slope which is related to the duration and volumn of rain water downpour. We have to check externally that the seep holes are not blocked.
(3) Soil stability test
The soil stability test carrid out by the said authority is only for slope belonging to the local authority/government such as forest reserves. They will study and look into the boundary plan of this development for this purpose.
Your kind attention is appreciated.
Posted by 黄世成 at 9:39 PM