RISK MANAGEMENT OF DIAPHRAGM WALL CONSTRUCTION

AFFECTING ADJACENT BUILDINGS

A CASE STUDY OF CONSTRUCTION PROJECT

IN HO CHI MINH CITY, VIETNAM

By

Huynh Thanh Quang

Abstract

In Vietnam was, is and will construct several buildings with basements. The construction of the basement in the soft ground in urban areas is more difficult and risky. There have been many successes but also happened to shame. There are many causes affecting the displacement of the structure and the land around the pit with and without adjacent works. Due to the urgent problem is mentioned so many studies summarizing the experience in the design and construction of over. This project report studied about risk management of basement construction affecting adjacent buildings.

We can only avoid the risks have clearly defined the cause risks to be proactive prevention measures in quality control work is to manage every stage of investment preparation, performance investment and exploitation. To limit risks in this problem, we must to risk identification and solving methods of risk in preparing and constructing stage of diaphragm wall and basements. Although many projects have quality management system, but risk still occurs, and even causing very severe damages for surrounding building.

Therefore, risk identification is the problem very important in quality management system of the project.

Executive summary

Rationale of research

This research has been conducted to identify risk in construction of Diaphragm wall.

Objectives of study

To identify the risk factors involving construction of Diaphragm wall and its effects on surrounding buildings and to propose recommendations to  reduce its effect on surrounding buildings.

Methodology  

The exploratory research method is used to study Diaphragm wall construction process by analyzing case of a building construction project Ho Chi Min City Vietnam.

Findings and conclusion

We can only avoid risks when we identified the cause of risk clearly and made a proactive and preventive measure in project quality management. So, the cause analysis of incident, technical error should be considered large study range in the development strategy of science and technology. Practice shows that many building was caused incidents in execution process of basement, it create severe impact such as structure damages, non-uniform settlement, collapse, casualties etc, some of the problems happened at site are as flows.

·         Damages to the adjacent buildings due to movement of machines and vibration caused by execution of diaphragm wall and bored piles, it will bad impact on the adjacent buildings.

·         Increasingly local deformation of the diaphragm walls made surrounding soil deformed.

·         Defect on the diaphragm wall have occurred pierced holes at basement.

We can see the above reasons are due to less experience of managers. Besides, the investor and relevant parties does not expected budget for risks. If the funding to solving of risks have not or not enough, plans for risk management will be limited and not efficient.

Recommendations

Limit and control of incident are a very complicated task; it requires high level experienced experts and responsibility before the work. Before design and building construction, the consultant must be to investigate the surrounding building thorough, to clarify the position, the status of the building, underground structure, roads, underground pipes, etc, currently in incidence, and estimated affect about adjacent building due to pumping lower ground water level and basement excavation. The contractor must be proposed method to prevent, control, observation and deal with urgent incidents when they happen.

The risks might cause severe incidents (Defect on diaphragm wall (pierced holes), deformation of shoring and king-post system, settlement of adjacent building, displacement of diaphragm wall, etc), there solving problem when it happened is quick enough and thoroughly. They must have plans to deal with urgent incidents and to focus on manpower, equipment and finance to solving risks. Besides, when incident happen they must to displacement and settlement observation for the building and adjacent building. Moreover, they should be study geologic conditions inside and outside the building, this problem is also very important in during process of observing and solving incidents, even solution to move people exit dangerous area when incidents happen.