How to calculate foundation pit excavation?
Foundation pit excavation is an important part of construction engineering, and its calculation involves multiple parameters and steps. This article will combine the hot topics and content of the past 10 days to introduce the calculation method of foundation pit excavation in a structured way and provide relevant data tables for reference.
1. Basic concepts of foundation pit excavation
Foundation pit excavation refers to the excavation of earth for the construction of underground structures (such as basements, underground garages, etc.). The calculation mainly includes earthwork volume, slope stability, supporting structure design, etc. The following are common calculation steps for foundation pit excavation:
| Calculation project | Calculation formula | illustrate |
|---|---|---|
| Earthwork volume | V = (A1 + A2) × L / 2 | A1 and A2 are the cross-sectional areas at both ends of the foundation pit, and L is the length of the foundation pit. |
| Slope slope | i=H/B | H is the excavation depth, B is the width of the slope bottom |
| Supporting structure stress | F = γ × H × Ka | γ is the soil weight, Ka is the active earth pressure coefficient |
2. Calculation steps for foundation pit excavation
1.Determine the scope of excavation: Determine the basic parameters such as the length, width and depth of the foundation pit according to the design drawings.
2.Calculate earthwork volume: Use segmentation method or grid method to calculate earthwork volume to ensure accuracy.
3.Slope design: Determine the slope slope according to soil conditions to ensure stability during excavation.
4.Support structure design: Select appropriate support methods (such as steel sheet piles, underground diaphragm walls, etc.) and calculate their stress conditions.
3. Precautions for foundation pit excavation
1.geological conditions: Before excavation, a geological survey is required to understand the distribution of soil layers and groundwater levels.
2.Surrounding environment: Pay attention to the impact of surrounding buildings and underground pipelines to avoid settlement or damage caused by excavation.
3.security measures: Set up safety warning signs and provide necessary support and drainage facilities.
4. Frequently Asked Questions about Foundation Pit Excavation
| question | reason | solution |
|---|---|---|
| slope collapse | The soil is soft or the slope design is unreasonable | Reinforce slopes or adjust slopes |
| Water accumulation in foundation pit | Inadequate drainage system | Add drains or water pumps |
| Deformation of supporting structure | Too much force or unqualified materials | Strengthen support or replace materials |
5. Case analysis of foundation pit excavation
Taking the excavation of a foundation pit for a commercial complex as an example, the excavation depth is 10 meters and the earthwork volume is approximately 50,000 cubic meters. Through segment calculation and slope optimization, the project was successfully completed and 10% of the construction period was saved. Here are the key figures for the project:
| project | numerical value | unit |
|---|---|---|
| Excavation depth | 10 | rice |
| Earthwork volume | 50,000 | cubic meter |
| Slope slope | 1:1.5 | - |
| Support method | underground continuous wall | - |
6. Summary
The calculation of foundation pit excavation is a complex and important task that requires comprehensive consideration of geology, environment, construction conditions and other factors. Through scientific calculation and reasonable design, the safety and economy of foundation pit excavation can be ensured. We hope that the content of this article can provide reference for relevant engineering personnel.
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