Geo-Environment Suitability Evaluation for Urban Construction in Rongcheng District of **ong’an New Area, China
Abstract
:1. Introduction
2. Study Area
3. Methods
3.1. Field Survey and Data Collection
3.2. Comprehensive Evaluation Frame
3.3. Evaluation Method
- (1)
- Establish an importance matrix, A.
- (2)
- Identify the weights
- (3)
- Calculate the suitability comprehensive index, SI.
4. Results and Discussion
4.1. Results and Discussion of Geo-Environment Indicator Distribution
4.1.1. Bearing Capacity of Foundation Soils
4.1.2. Land Subsidence
4.1.3. Geological Faults
4.1.4. Ground Fissures
4.1.5. Potential Liquefied Sands
4.1.6. Qualities of Groundwater and Soil Chemistry
4.1.7. Chemical Corrosion of Concrete and Steel by Groundwater
4.1.8. Enrichment of Deep Groundwater and Geothermal Resource
4.2. Results and Discussion of Geo-Environment Suitability for Urban Construction
5. Conclusions
- (1)
- In order to evaluate the geo-environment suitability for urban construction in Rongcheng district of **ong’an New Area, the analytic hierarchy process (AHP) integrated GIS overlay analysis was used, based on the construction of a comprehensive evaluation frame. Moreover, two criteria, consisting of geological conditions and resource conditions, were taken into consideration for suitability evaluation, including four subcriteria, i.e., engineering geological status, environmental geological status, hydrogeological status, and resource guarantee status, which involved 15 indicators. Regrettably, the evaluation did not include the compressibility indicator of foundation soils due to a lack of data. When evaluating the suitability of the geo-environment for urban construction in other areas with the AHP method, more indicators of foundation soils could be taken into consideration. Furthermore, the analytic hierarchy process has certain advantages compared to other methods, such as the artificial neural network method and grey comprehensive evaluation method. It not only provides a quantitative mathematical calculation, but also incorporates the comparative judgment of geological experts regarding the importance of different geological indicators.
- (2)
- The evaluation results showed that the geo-environment suitability for urban construction in most areas was in high and very high grades, of which, the very high zone covered an area of about 98 km2, and the high zone was nearly 182 km2. The acreage of the moderate grade was approximately 5.5 km2, and the low grade was close to 28.5 km2. The most suitable areas for urban construction, with an acreage percentage of 31.2%, were mainly located in the central parts of the study area. In the meantime, the least suitable areas, with an acreage percentage of 9.1%, were situated in the southeast corner and three linear belts.
- (3)
- It is crucial to emphasize that faults, land subsidence rate, and potential liquefied sands are the primary factors that influence decision-making regarding future construction activities. When urban construction takes place in areas close to faults, buildings should maintain a certain distance from them, and these areas should be designated as green spaces. In regions experiencing a land subsidence rate of more than 30 mm/a, it is advisable to reduce groundwater extraction and lower the height of planned buildings. Additionally, engineering protection measures should be implemented in areas with potential liquefied sands. By addressing these issues, the study area can reduce infrastructure construction costs, and minimize the risk of geological disasters.
Author Contributions
Funding
Scale | Meaning of the Scale |
---|---|
Scale = 1 | Equal importance, two indicators contribute equally to the object |
Scale = 1/9 | Extreme unimportance, the evidence favoring one indicator over another is of the lowest possible order of affirmation |
1/9 < Scale < 1,
1 < Scale < 9 | More and more importance, judgment more and more strongly favors one indicator over another |
Scale = 9 | Extreme importance, the evidence favoring one indicator over another is of the highest possible order of affirmation |
Order-Number | 11 | 12 | 13 | 14 | 15 |
RI value | 1.51 | 1.48 | 1.56 | 1.57 | 1.59 |
Criteria Layer | Subcriteria Layer | Indicator Layer | Grading Criteria of Suitability | ||||
---|---|---|---|---|---|---|---|
Very High | High | Moderate | Low | ||||
Geological conditions | Engineering geological status | Bearing capacity of foundation soils | 0~5 m (C1) | 125~130 kpa | 115~125 kpa | 105~115 kpa | / |
5~10 m (C2) | 140~180 kpa | 130~140 kpa | 120~130 kpa | 110~120 kpa | |||
10~15 m (C3) | 190~250 kpa | 170~190 kpa | 150~170 kpa | 110~150 kpa | |||
15~30 m (C4) | 185~240 kpa | 175~185 kpa | 165~175 kpa | 155~165 kpa | |||
30~50 m (C5) | 220~280 kpa | 210~220 kpa | 200~210 kpa | 190~200 kpa | |||
Environmental geological status | Land subsidence rate (C6) | <0 mm/a | 0~10 mm/a | 10~30 mm/a | >30 mm/a | ||
Geological faults (C7) | None | Away | Near | Existing | |||
Ground fissures (C8) | None | Away | Near | Existing | |||
Potential liquefied sands (C9) | None | Slight | Moderate | ||||
Quality of groundwater chemistry (C10) | Can be used as a source of drinking water | Can be used as drinking water after proper treatment | Not suitable to be a source of drinking water | ||||
Quality of soil chemistry (C11) | Very clean | Clean | Mildly polluted | Serious polluted | |||
Resource conditions | Hydrogeological status | Chemical corrosion of concrete by groundwater (C12) | Slight | ||||
Chemical corrosion of steel by groundwater (C13) | Slight | A little | |||||
Resource Guarantee status | Enrichment of deep groundwater (C14) | >5000 m3/d | 3000–5000 m3/d | 1000–3000 m3/d | <1000 m3/d | ||
Geothermal resource/Geothermal gradient (C15) | ≥6 °C/100 m | ≥5 °C/100 m | ≥3 °C/100 m | <3 °C/100 m |
C1 | C2 | C3 | C4 | C5 | C6 | C7 | C8 | C9 | C10 | C11 | C12 | C13 | C14 | C15 | Weights | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
C1 | 1 | 1 | 1 | 5/4 | 5/4 | 5/8 | 5/9 | 5/4 | 5/7 | 5/3 | 5/1 | 5/4 | 5/4 | 6/5 | 5/4 | 0.07 |
C2 | 1 | 1 | 5/4 | 5/4 | 5/8 | 5/9 | 5/4 | 5/7 | 5/3 | 5/1 | 5/4 | 5/4 | 6/5 | 5/4 | 0.07 | |
C3 | 1 | 5/4 | 5/4 | 5/8 | 5/9 | 5/4 | 5/7 | 5/3 | 5/1 | 5/4 | 5/4 | 6/5 | 5/4 | 0.07 | ||
C4 | 1 | 1 | 1/2 | 4/9 | 6/5 | 2/3 | 3/2 | 4/1 | 6/5 | 6/5 | 7/6 | 6/5 | 0.06 | |||
C5 | 1 | 1/2 | 4/9 | 6/5 | 2/3 | 3/2 | 4/1 | 6/5 | 6/5 | 7/6 | 6/5 | 0.06 | ||||
C6 | 1 | 7/9 | 2/1 | 8/7 | 4/1 | 5/1 | 8/3 | 8/3 | 8/3 | 4/1 | 0.12 | |||||
C7 | 1 | 9/4 | 9/7 | 9/4 | 6/1 | 3/1 | 8/3 | 9/4 | 3/1 | 0.13 | ||||||
C8 | 1 | 4/7 | 2/1 | 2/1 | 4/5 | 4/5 | 5/2 | 5/3 | 0.06 | |||||||
C9 | 1 | 7/3 | 7/3 | 7/4 | 7/4 | 2/1 | 7/3 | 0.09 | ||||||||
C10 | 1 | 8/7 | 1/2 | 1/2 | 7/9 | 7/8 | 0.04 | |||||||||
C11 | 1 | 1/4 | 1/4 | 1/3 | 1/2 | 0.02 | ||||||||||
C12 | 1 | 1 | 5/4 | 5/3 | 0.06 | |||||||||||
C13 | 1 | 5/4 | 5/3 | 0.06 | ||||||||||||
C14 | 1 | 4/3 | 0.05 | |||||||||||||
C15 | 1 | 0.04 |
Grade | Acreage (sq.km.) | Percentage | Main Affecting Factors |
---|---|---|---|
Very high | 98 | 31.2% | Geothermal resource |
Enrichment of deep groundwater | |||
Characteristic value of bearing capacity of foundation soil | |||
High | 182 | 58% | Characteristic value of bearing capacity of foundation soil |
Quality of groundwater chemistry | |||
Moderate | 5.5 | 1.7% | Ground fissures |
Chemical corrosion of concrete by groundwater | |||
Chemical corrosion of steel by groundwater | |||
Quality of soil chemistry | |||
Low | 28.5 | 9.1% | Geological faults |
Land subsidence rate | |||
Potential liquefied sands |
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© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
Liu, H.; Han, B. Geo-Environment Suitability Evaluation for Urban Construction in Rongcheng District of **ong’an New Area, China. Appl. Sci. 2023, 13, 9981. https://doi.org/10.3390/app13179981
Liu H, Han B. Geo-Environment Suitability Evaluation for Urban Construction in Rongcheng District of **ong’an New Area, China. Applied Sciences. 2023; 13(17):9981. https://doi.org/10.3390/app13179981
Chicago/Turabian StyleLiu, Hongwei, and Bo Han. 2023. "Geo-Environment Suitability Evaluation for Urban Construction in Rongcheng District of **ong’an New Area, China" Applied Sciences 13, no. 17: 9981. https://doi.org/10.3390/app13179981