Research on the deformation mechanism and law caused by the influence of seepage on foundation pit dewatering

The thickness of aquifer is relatively large, the aquifer is not completely isolated by the diaphragm wall, and the water flow inside and outside the foundation pit flows at the bottom of the diaphragm wall. This article reports indoor experiments and theoretical methods which are used to study the...

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Main Authors: Qingyuan Yang, Song Chen
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-01-01
Series:Frontiers in Earth Science
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Online Access:https://www.frontiersin.org/articles/10.3389/feart.2024.1523165/full
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author Qingyuan Yang
Song Chen
author_facet Qingyuan Yang
Song Chen
author_sort Qingyuan Yang
collection DOAJ
description The thickness of aquifer is relatively large, the aquifer is not completely isolated by the diaphragm wall, and the water flow inside and outside the foundation pit flows at the bottom of the diaphragm wall. This article reports indoor experiments and theoretical methods which are used to study the deformation mechanism and law caused by dewatering in foundation pit under the condition of incomplete isolation of the inner and outer aquifers of the foundation pit based on typical geological conditions in South China. Our findings are as follows. (1) Through the experimental analysis of the mechanism of groundwater seepage around the foundation pit, the effective influence depth of precipitation in the foundation pit is greater than that outside the foundation pit, and the effective influence depth of double well precipitation is greater than that of single well precipitation. It reveals that the precipitation curve outside the foundation pit under the influence of seepage around the foundation pit presents the characteristics, and puts forward the calculation formula of surface settlement change outside the pit caused by partially penetrating well precipitation in the completely decomposed granite stratum. The calculation results of the theoretical formula are in good agreement with the experimental results, which has good accuracy and applicability. (2) The surface settlement outside the pit caused by dewatering in the foundation pit is mainly concentrated in the surrounding seepage area, and the change value of surface settlement outside the pit caused by double well dewatering is 2∼3 times greater than that caused by single well dewatering. When the whole well is vertically reinjected, the maximum surface settlement is 0.009 mm at the side near the diaphragm wall, and 0.005 mm at the side far away from the diaphragm wall. When the whole well is at an inclination of 10°, the maximum surface settlement is 0.002 mm at the side near the diaphragm wall, and 0.008 mm at the side far away from the diaphragm wall. When the whole well is at an inclination of 20°, the maximum surface settlement is −0.005 mm at the side near the diaphragm wall, and 0.011 mm at the side far away from the diaphragm wall. The full well depth recharge with an inclination of 20° has the largest influence on the surface settlement of the foundation pit, and the recharge effect is the best. (3) The lateral displacement of diaphragm wall increases by 24% compared with that without reinjection. The maximum lateral displacement of the diaphragm wall is 0.09% of the precipitation depth when the whole well is tilted at 10° for reinjection, and the lateral displacement of the diaphragm wall increases by 13% compared with that without reinjection. The maximum lateral displacement of the diaphragm wall is 0.082% of the precipitation depth when the whole well is tilted at 20° for reinjection, and the lateral displacement of the diaphragm wall increases by 4.9% compared with that without reinjection. The full well depth recharge with an inclination of 20° has the least impact on the diaphragm wall, and the recharge effect is the best. The above results can be provided as theoretical foundation for the study of the deformation mechanism and law caused by dewatering in foundation pit.
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spelling doaj-art-8571dd7131a2453a9aee13b6e1b3da562025-01-22T07:12:56ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632025-01-011210.3389/feart.2024.15231651523165Research on the deformation mechanism and law caused by the influence of seepage on foundation pit dewateringQingyuan Yang0Song Chen1School of Architecture and Engineering, Guangzhou Panyu Polytechnic, Guangzhou, ChinaHebei Center for Ecological and Environmental Geology Research, Hebei GEO University, Shijiazhuang, ChinaThe thickness of aquifer is relatively large, the aquifer is not completely isolated by the diaphragm wall, and the water flow inside and outside the foundation pit flows at the bottom of the diaphragm wall. This article reports indoor experiments and theoretical methods which are used to study the deformation mechanism and law caused by dewatering in foundation pit under the condition of incomplete isolation of the inner and outer aquifers of the foundation pit based on typical geological conditions in South China. Our findings are as follows. (1) Through the experimental analysis of the mechanism of groundwater seepage around the foundation pit, the effective influence depth of precipitation in the foundation pit is greater than that outside the foundation pit, and the effective influence depth of double well precipitation is greater than that of single well precipitation. It reveals that the precipitation curve outside the foundation pit under the influence of seepage around the foundation pit presents the characteristics, and puts forward the calculation formula of surface settlement change outside the pit caused by partially penetrating well precipitation in the completely decomposed granite stratum. The calculation results of the theoretical formula are in good agreement with the experimental results, which has good accuracy and applicability. (2) The surface settlement outside the pit caused by dewatering in the foundation pit is mainly concentrated in the surrounding seepage area, and the change value of surface settlement outside the pit caused by double well dewatering is 2∼3 times greater than that caused by single well dewatering. When the whole well is vertically reinjected, the maximum surface settlement is 0.009 mm at the side near the diaphragm wall, and 0.005 mm at the side far away from the diaphragm wall. When the whole well is at an inclination of 10°, the maximum surface settlement is 0.002 mm at the side near the diaphragm wall, and 0.008 mm at the side far away from the diaphragm wall. When the whole well is at an inclination of 20°, the maximum surface settlement is −0.005 mm at the side near the diaphragm wall, and 0.011 mm at the side far away from the diaphragm wall. The full well depth recharge with an inclination of 20° has the largest influence on the surface settlement of the foundation pit, and the recharge effect is the best. (3) The lateral displacement of diaphragm wall increases by 24% compared with that without reinjection. The maximum lateral displacement of the diaphragm wall is 0.09% of the precipitation depth when the whole well is tilted at 10° for reinjection, and the lateral displacement of the diaphragm wall increases by 13% compared with that without reinjection. The maximum lateral displacement of the diaphragm wall is 0.082% of the precipitation depth when the whole well is tilted at 20° for reinjection, and the lateral displacement of the diaphragm wall increases by 4.9% compared with that without reinjection. The full well depth recharge with an inclination of 20° has the least impact on the diaphragm wall, and the recharge effect is the best. The above results can be provided as theoretical foundation for the study of the deformation mechanism and law caused by dewatering in foundation pit.https://www.frontiersin.org/articles/10.3389/feart.2024.1523165/fullfoundation pit dewateringmodel testeffective influencing depthdewatering curvedeformation lawreinjection form
spellingShingle Qingyuan Yang
Song Chen
Research on the deformation mechanism and law caused by the influence of seepage on foundation pit dewatering
Frontiers in Earth Science
foundation pit dewatering
model test
effective influencing depth
dewatering curve
deformation law
reinjection form
title Research on the deformation mechanism and law caused by the influence of seepage on foundation pit dewatering
title_full Research on the deformation mechanism and law caused by the influence of seepage on foundation pit dewatering
title_fullStr Research on the deformation mechanism and law caused by the influence of seepage on foundation pit dewatering
title_full_unstemmed Research on the deformation mechanism and law caused by the influence of seepage on foundation pit dewatering
title_short Research on the deformation mechanism and law caused by the influence of seepage on foundation pit dewatering
title_sort research on the deformation mechanism and law caused by the influence of seepage on foundation pit dewatering
topic foundation pit dewatering
model test
effective influencing depth
dewatering curve
deformation law
reinjection form
url https://www.frontiersin.org/articles/10.3389/feart.2024.1523165/full
work_keys_str_mv AT qingyuanyang researchonthedeformationmechanismandlawcausedbytheinfluenceofseepageonfoundationpitdewatering
AT songchen researchonthedeformationmechanismandlawcausedbytheinfluenceofseepageonfoundationpitdewatering