Intro
If buoyancy (uplift pressure) due to groundwater is not properly evaluated during the construction or completion of structures, it can have a significant impact on the stability of soil and underground parts of the structures. Therefore, it is necessary to take appropriate technical measures during design and construction in order to manage its harmful influence.
It is necessary to design a stable structure by reviewing the forces and resistances caused by the upward hydrostatic buoyancy (U) acting on the bottom of the structure where groundwater exists between the ground and the structure. These include the structure's weight (W1), overburden pressure (W2), and frictional force (Ps).
The MIDAS CIVIL NX modeling provides convenience by allowing an easy buoyancy review, thus facilitating the evaluation of buoyancy stability.
Version
- v1.0.0 : Plugin release
Applicable Standards
- General Use
Benefits of this plugin
This plug-in automatically calculates the self-weight of the structure based on the Midas Civil NX model. Additionally, users can define the structure to be reviewed and perform buoyancy evaluations during construction.
This plug-in considers various resistance conditions against buoyancy:
-
Shear key
-
Shear friction force
- Review during construction (ignoring overburden pressure)
- Additional overburden load conditions
The buoyancy stability assessment results are provided in real-time based on the review conditions, facilitating efficient buoyancy evaluations.
This plugin facilitates preliminary reviews and allows for comparisons with detailed calculation reports prepared by designers to prevent errors.
How to use this plugin?
1. Select the defined buoyancy review stage (by default, it automatically loads the entire model in CIVIL NX).
2. Define additional review stages.
3. Set the resistance conditions.
4. Define the soil cover depth and groundwater level (GL-).
5. Detailed settings for conditions and properties of the buoyancy review can be defined.
6. Calculated forces and resistances (U: buoyancy, W1: self-weight, W2: earth pressure, Ps: frictional force).
7. Enter the safety factor (F.S.) and check the buoyancy stability results.
2.1. Define the name of the set to be saved.
2.2. Select elements in Civil, and when you click in the plugin, the information is automatically transferred.
2.3. Save the defined set.
2.4. Manage the saved sets.
Soil Input
Soil Density : Unit weight applied to the bearing earth pressure
Submerged soil weight : Submerged unit weight applied to the bearing earth pressure
Internal friction angle : Internal friction angle
Water density : Unit weight of groundwater
Added Load Input
Waterproof thickness : Thickness of waterproof mortar
Waterproof units dry weight : Unit weight of waterproof mortar
Waterproof units sub weight : Submerged unit weight of waterproof mortar
Added load thickness : Thickness of additional load
Added load unit weight : Unit weight of additional load
Conclusion
By conducting convenient reviews based on Midas civil NX modeling, this method enables quicker and more convenient buoyancy stability assessments compared to the traditional approach of manually calculate reports