The square's central area covers more than 23,000 square metres and comprises two sections built on different foundations.
The semicircular section is built on reinforced concrete supported by piles averaging 14 metres deep. The remaining 11,700-square-metre section facing 23/3 Street sits on a six-to-14-metre-high earth embankment containing about 205,000 cubic metres of fill.
The subsidence and cracks have appeared near the boundary between the reinforced-concrete section and the area built on filled ground.
Lam Dong Province's Construction Investment Project Management Board No. 3, the project investor, said settlement of the high earth embankment had been anticipated during the design stage.
Technical calculations project settlement of between 18 and 69 centimetres over 15 years, depending on location, including 12-33 centimetres during the first two years.
Uneven settlement can cause the paving above to crack, loosen or break, the board said.
The investor said the affected area of about 700 square metres mainly involved surface finishes and showed no signs of compromising the main load-bearing structure.
The square remains safe for events and public activities, it added.
The project management board will work with designers and contractors to monitor the extent of settlement and compare it with design parameters.
Damaged paving stones will be repaired or replaced under warranty once the ground has stabilised sufficiently to avoid repeated repairs.
Gia Nghia Square opened on July 25 and is one of Lam Dong Province's major cultural and urban infrastructure projects.