TNF Technology - Vina Takeuchi

Overview of TNF method

TNF construction method is a grid pattern structure integrating the foundation and the ground inprovement layer.

T – Tender
N – Net
F – Foundation

Patent

Special foundation methods for soft ground conditions
Patent No. 3608586
Acquisition date: October 22, 2004

Examination certification
Quality inspection method using SWS test for TNF construction technology for civil and industrial projects.
Certificate: BL examination certificate-031
Acquisition date: December 2017

A grid pattern structure integrating the foundation and the ground improvement layer

By integrating the ground reinforcement layer, the foundation, and the slab, the load from the column can be transferred to not only the foundation under the column but also to the supporting soil through the reinforcement layer from the slab surrounding the foundation.
In addition, when the bottom of the reinforcement layer, the surface touching the supporting layer, is in a grid pattern, the load is transferred to the ground in a way that makes energy work to hold the soil at the hollow part and prevent it from going out.
It will be stable as the way the load is transferred supports the building.
We call it the “TNF enclosure effect,” i.e., an outstanding feature of TNF construction method.

Pile-free construction of a low-cost foundation

TNF construction method usually does not have underground beams. The foundation and the concrete slab are directly installed in the reinforcement layer, which is made in a grid pattern.
The load of the building can be efficiently transferred onto the supporting soil because the reinforcement layer, the foundation, and the slab are integrated.
Conventionally, the pile foundation system that uses the strong lower layer as the supporting layer is the main stream when the surface layer is soft and weak, but with the TNF construction method, a low-cost foundation without piles can be made because it can use the surface layer as the supporting layer.

Differences between TNF construction method and pile foundation system

POINT 1: NO UPLIFTIN

POINT 2: SAFE FOR UNDERGROUND PIPE SYSTEM

POINT 3: EASE OF DISMANTLING AT A LOW COST

POINT 4: THE GROUND CAN BE SHALLOW

Overview of TNF2.0 method

TNF2.0 is an improvement of TNF construction method with lower cost, safer and more secure.

TNF2.0 construction method improves the ground highly efficiently according to the stress distribution, helping to reduce relative settlement, while maximizing material savings.

Patents:

Ground reclamation with high efficiency based on stress distribution
Patent No.: 7175054
Issue Date: November 10, 2022

Improvement according to the stress distribution

With TNF2.0, the improvement thickness will change based on the stress distribution.
TNF2.0 reduces material costs while minimizing settlement.

Reduce improvement amount

Ground stress at the bottom of the improvement

The ground stress in the middle zone of the improvement ground is reduced, so the ground stress at the bottom of the improvement ground will be better distributed.

The ground stress at the bottom of the foundation is also more evenly distributed.

Middle zone stress: Decreases; Boundary zone stress: Increases

→ The difference in settlement between the inside and outside is reduced, so the differential settlement is reduced.

Effective settlement reduction

Absolute settlement reduces about 13%.

Relative settlement reduces about 24%.

Apply TNF in Vietnam

Current situation of weak soil in Vietnam

The major urban centers of Vietnam, namely Hai Phong and Ho Chi Minh City, are situated within the basins of the Red River and Mekong Delta. As a result, these cities possess fertile alluvial soil and abundant deposits of soft clay. Constructing houses, roads, industries, and other structures on soft soil presents several challenges that need to be addressed, including issues like the limited load-bearing capability of the foundation, significant settlement, and substantial differential settlement.

The problems of the pile foundation scheme

So far, a series of weak ground treatment technologies have been applied in Vietnam. Current measures such as pile foundations can overcome the load strength and settlement for the project, but they have not overcome some problems such as large settlements, high costs, and complicated construction machinery.

The survey results of works in Ho Chi Minh City show that the subsidence of the ground outside the building, causing damage to the building, is a common phenomenon in works on weak ground using the pile method. With the use of pile foundations, when the soil around the project subsidences a lot while the settlement of the building is less, it will lead to cracking of the base, and in some cases, the pile head may be exposed.

In addition, the cost to construct piles is also quite expensive, due to the use of many complex machines to construct piles and the long construction time.

The advantages of TNF construction method for weak soils

For the building damage problems mentioned above, TNF will solve them optimally and effectively. The project applying TNF has the ability to minimize the subsidence of the project. In fact, TNF has been verified to limit subsidence when compared to neighboring buildings using the pile method.

The optimization of TNF is also reflected in the use of simple construction machines, so the maneuvering of machines will be easier and faster. This helps reduce construction time and construction costs for the project.

Given the aforementioned benefits, the TNF weak soil treatment technology will consistently evolve to cater to the demands of development projects in Vietnam.