Vong Phu Rock looks 'different' after a 17 billion VND investment in reinforcement.

(CLO) The national historical site of Vong Phu Rock in Thanh Hoa has just completed reinforcement work to prevent collapse at a cost of 17 billion VND, revealing a "unique" appearance.

The Vong Phu Rock, a famous cultural symbol in Thanh Hoa province, has just officially completed its reinforcement process.

In May 2025, the People's Committee of Thanh Hoa province approved the investment project for the construction of a conservation and reinforcement project for the Vong Phu rock formation, part of the An Hoach mountain (Nhoi mountain) art and scenic complex, formerly located in An Hung ward, Thanh Hoa city, now Dong Quang ward, Thanh Hoa province.

The Vong Phu rock formation has a new look, with white as the dominant color. Photo: Pham Truong

The total investment for the project is 17 billion VND from the provincial budget, with the Thanh Hoa Provincial Management Board for Investment and Construction of Civil and Industrial Works acting as the investor.

According to the approved conservation project, the solution to ensure that the rock formations of Vong Phu is not separated is to use core drilling, followed by reinforcement with steel wires embedded in Sika Grout 214-11, reinforcing them vertically.

When Sika grout is injected, the grout fills the cracks in the borehole walls, enveloping the D14 steel wires, forming strong bonds capable of withstanding both tensile and compressive forces. This prevents crack growth and binds the disparate elements of the rock mass into a unified, solid structure.

The construction unit used reinforcing steel anchors consisting of three D14 steel bars, CB500-V type (critical strength 500 MPa), with a tensile strength of 21.47 tons per bundle. The three steel bars were welded together, and the bundle was placed into a D76 core drilling pipe, starting from the top of the rock mass and anchored deep into the base.

To prevent the separation of rock formations around the outer surface of Vong Phu rock, the construction unit used Sika Grout 214-11 to fill all the cracks.

Image of Vong Phu Rock before it was reinforced. (Archival photo)

Previously, according to a report from the Department of Culture, Sports and Tourism of Thanh Hoa province, Vong Phu rock formation had been struck by lightning several times, causing landslides in two locations. On the western side near the summit, a rock mass of approximately 1m x 3m collapsed, while on the eastern side, a rock mass of 2.5m x 3m collapsed.

Following the incident, Vong Phu rock formation continued to erode, developing numerous cracks and currently tilting at an angle of 10-15 degrees. It is at risk of further lightning strikes causing its collapse if protective and conservation measures are not implemented soon.

In October 2023, the Department of Culture, Sports and Tourism of Thanh Hoa province organized a workshop to assess the current situation and propose solutions for preserving the Vong Phu rock formation. By mid-2024, Thanh Hoa city had invested over 800 million VND in a lightning protection system at the site.

Hon Vong Phu is a rock column about 20 meters high, resembling a woman holding a child. The site was recognized as a National Monument by the Ministry of Culture, Sports and Tourism in 1992.

Source: https://congluan.vn/hon-vong-phu-khac-la-sau-khi-duoc-dau-tu-17-ty-dong-gia-co-10326915.html