Disaster-Causing Mechanism of the Continuous Failure of Deep Foundation Pits in Tropical Water-Rich Sandy Strata DOI Creative Commons
Ping Lu,

Zheng Shao,

Jiangang Han

et al.

Applied Sciences, Journal Year: 2024, Volume and Issue: 15(1), P. 72 - 72

Published: Dec. 26, 2024

To investigate the mechanisms underlying continuous failure of deep foundation pits in tropical water-rich sandy strata, this study comprehensively examines a pit project Haikou city, China. Using PLAXIS3D 24.1 software, three-dimensional finite element numerical model was developed. The analysis integrates design schemes, field investigations, monitoring data, and other relevant information to elucidate disaster damage, such as water inrush, floor collapse, sidewall failure. results indicate that barrier layer is thinnest at elevator shaft pit, with rapid shortening seepage paths following extraction steel sheet piles; velocity increases by approximately 120%, leading groundwater breaching both cushion layers. inadequate length suspended impervious curtain confined aquifer maximum defect site 40 times greater than locations, facilitating influx into pit. As excavation deepens, significant alterations occur location water-resisting curtain, increasing from 6.4 mm/day outside 78.8 inside thereby threatening stability foundation. Additionally, construction quality defects arising three-axis mixing method silty sand cause downward shift horizontal displacement supporting structure, increments near reaching 63%. Unreasonable emergency pumping measures can lead collapses damage. soil significantly affects back pressure, but it also affected distance, increase remains under 1% does not impact damaging incident.

Language: Английский

The Field Monitoring and Numerical Simulation of Spatiotemporal Effects During Deep Excavation in Mucky Soft Soil: A Case Study DOI Creative Commons
Qiang Wu, Jianxiu Wang, Yanxia Long

et al.

Applied Sciences, Journal Year: 2025, Volume and Issue: 15(4), P. 1992 - 1992

Published: Feb. 14, 2025

The issue of geotechnical hazards induced by excavation in soft soil areas has become increasingly prominent. However, the retaining structure and surface settlement deformation creep spatial effect sequence are not fully considered where only elastic–plastic is used design. To understand spatiotemporal effects excavation-induced pits, a case study was performed with Huaxi Park Station Suzhou Metro Line S1, Jiangsu Province, China, as an example. Field monitoring conducted, three-dimensional numerical model developed, taking into account characteristics mucky clay response structures excavations. ground during processes were analyzed. results show that depth increased, horizontal displacement diaphragm walls increased linearly tended to exhibit abrupt changes when approaching bottom pit. maximum wall at west end well close 70 mm, standard section reached approximately 80 mm. on both pit sides showed “trough” distribution pattern, peaking about 12 m from edge, rate −1.9 mm/m per meter depth. process directly led lateral walls, resulting settlement, which prominently reflected time-dependent process. These findings provide critical insights for similar deep projects soil, particularly regarding deformations, providing guidance design standards strategies geological conditions.

Language: Английский

Citations

0
Observation and Analysis of Deformation Control Performance of Hydraulic Servo Steel Support for a Soft Soil Pit—A Case Study of a Pit Project in Hangzhou DOI Creative Commons
Chao Wang,

Gang Lin,

Hongliang Yao

et al.

Buildings, Journal Year: 2025, Volume and Issue: 15(7), P. 1002 - 1002

Published: March 21, 2025

As foundation pit engineering is developing towards larger and deeper designs, the requirements for controlling excavation-induced deformation are becoming increasingly stringent, particularly in complex urban environments soft soil areas. In recent years, numerous projects have incorporated Hydraulic Servo Steel Support (HSSS) to actively manage axial forces of internal supports, which has achieved significant reductions displacement retaining structures (δD). An investigation cases areas revealed that average ratios δD excavation depth (H) pits with without servo control systems were 0.11% 0.38%, respectively. This study analyzed monitoring data related δD, outside pit, changes force supports a deep located Hangzhou City, China. The results indicated employing zoned HSSS effectively controlled δD. During stage, ensured remained below design threshold, although some persisted during dismantling stage. Additionally, adjustments affected adjacent common occurrence reverse pulling first-layer due action HSSS. Therefore, further optimization necessary enhance effectiveness.

Language: Английский

Citations

0
Surface Deformation Characteristics and Influencing Factors in Deep Foundation Pit Excavations for Subway Projects in Ningbo’s Soft Soil Area DOI Creative Commons
Gang Li, Feng Qin, Ning Yan

et al.

Buildings, Journal Year: 2025, Volume and Issue: 15(8), P. 1229 - 1229

Published: April 9, 2025

The development of underground spaces is crucial for modern urban environments, particularly in coastal cities with prevalent soft soil conditions. Deep foundation excavation works such areas present technical challenges due to complex deformation phenomena including settlement and the lateral displacement supporting structures. This study analyzes patterns associated deep pit excavations Ningbo’s by examining 10 cases subway station projects. evaluated relationship between maximum surface various engineering parameters using statistical comparative analyses also compared results each those other regional studies. indicate that multiple coupled parameters—the depth, diaphragm-wall-embedded depth ratio, support system stiffness, aspect ratio—significantly shape patterns. average ratio 0.64%, notably higher than regions as Hangzhou Shanghai. this averaged 0.37% depth. diaphragm walls and, addition, positive correlation at which occurred was hδhmax=He + 1.46. A emerged ground walls. But influence on will show different types relationships depending area geotechnical conditions, need be further investigated.

Language: Английский

Citations

0
Performance of adjacent metro tunnels during deep excavation: A case study in Hangzhou DOI

Zhaorui Lin,

Yalong Jiang, Changjie Xu

et al.

Transportation Geotechnics, Journal Year: 2025, Volume and Issue: unknown, P. 101585 - 101585

Published: May 1, 2025

Language: Английский

Citations

0
Disaster-Causing Mechanism of the Continuous Failure of Deep Foundation Pits in Tropical Water-Rich Sandy Strata DOI Creative Commons
Ping Lu,

Zheng Shao,

Jiangang Han

et al.

Applied Sciences, Journal Year: 2024, Volume and Issue: 15(1), P. 72 - 72

Published: Dec. 26, 2024

To investigate the mechanisms underlying continuous failure of deep foundation pits in tropical water-rich sandy strata, this study comprehensively examines a pit project Haikou city, China. Using PLAXIS3D 24.1 software, three-dimensional finite element numerical model was developed. The analysis integrates design schemes, field investigations, monitoring data, and other relevant information to elucidate disaster damage, such as water inrush, floor collapse, sidewall failure. results indicate that barrier layer is thinnest at elevator shaft pit, with rapid shortening seepage paths following extraction steel sheet piles; velocity increases by approximately 120%, leading groundwater breaching both cushion layers. inadequate length suspended impervious curtain confined aquifer maximum defect site 40 times greater than locations, facilitating influx into pit. As excavation deepens, significant alterations occur location water-resisting curtain, increasing from 6.4 mm/day outside 78.8 inside thereby threatening stability foundation. Additionally, construction quality defects arising three-axis mixing method silty sand cause downward shift horizontal displacement supporting structure, increments near reaching 63%. Unreasonable emergency pumping measures can lead collapses damage. soil significantly affects back pressure, but it also affected distance, increase remains under 1% does not impact damaging incident.

Language: Английский

Citations

0