Land subsidence in the area of Modena, Po Valley, Northern Italy

Land subsidence in the area of Modena, Po Valley, Northern Italy

153A 883399 Evshmtion and prediction of mimideace in old working areas sad prncticsl preventive measures against mining, damage to new structure Nishi...

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153A 883399 Evshmtion and prediction of mimideace in old working areas sad prncticsl preventive measures against mining, damage to new structure Nishida, T; Esaki, T; Aoki, K; Kameda, N Proc 3rd Imtomthnml Symposimn oR Laml Subshtemee, geMce, 19-23 Marclt 1984 P717-725. Publ Wallingford: IAHS, 1986

silty and clayey levels in the top 120m. Hydrological and geological conditions are described. Measured subsidence is in accordance with simple theoretical predictions. Differential settlements, due to subsoil anisotropy are evident. Some anomalies in groundwater chemistry are reported, which can be explained by squeezing of interstitial pore water from clays.

Lack of space necessitates construction over abandoned mines in Japan. The weight of the structure may be sufficient to instigate ground movement. Surface cave-in is common over shallow workings. The effects of such cavities can be remedied by deep pile or raft foundations, or by excavating and filling or grouting the cavities. Finite element analysis is used to predict subsidence for a power plant above deep abandoned workings.

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Sul~bace of llag0kok Clay dne to deep well lmmplng and its emtrni emmO artlaei,I r e d m l e Nutalaya, P; Chandra, S; Balasubramaniam, A S Proc 3rd lmermutmud Symposimn on La:ul Subsideaee, VeMee, 19-23 March 1984 P727-744. Publ Wallingford: IAHS, 1986 Bangkok lies on a layered soil system with aquifers separated by clay layers. Groundwater pumping has led to the lowering of the water table by 50m, and subsidence caused by consolidation of clay layers has reached worrying levels. A combined hydrologic and consolidation model of Bangkok has been developed and is used to explore the possibility of restoring piezometric head and arresting subsidence by artificial recharge.

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Eeeaemk imlmet of sudNNeace on water conveyenee in C~llforntg's San Joaquln Valley, USA Prokopovich, N P Proc 3rd imertwJimmi Symposimn on l a n d Subsidetwe, Vemc¢, 19-23 M u c k 1984 P795-804. Publ Wallingford: IAHS, 1986 Agriculture in this area is dependent on irrigation. Depletion of aquifers prior to surface water delivery by the Central Valley Project (CVP) caused subsidence of up to 9m, which necessitated rehabilitation of old and redesign of new CVP canals. Imported water is pumped from the Sacramento-San Joaquin Delta. This has led to subsidence of this tidal peat marsh, leading to levee breaks, flooding, and saline water intrusions requiring expensive remedial measures. Economic impact of subsidence and its future influence on the agricultural industry are considered.

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Iatnd mteideace In the area of Mndena, Po Valley, Northern

italy Colombetti, A; Gelmini, R; Pellegrini, M; Paltrinieri, N; Zavatti, A Proc 3rd lmerutiomd SympoMmn on Laml Ssbsidaee, Venice, 19-23 Marck 1954 P805-815. Publ Wallingford: IAHS, 1986 Subsidence of about lm has been recorded in Modena in the past decades, associated with a 10m drop in the piezometric surface, which has led to a drop in the pore pressure in the

C,eotedmleal conseqeences to the environment, by comtmetlen of the pekler Markerwaard

Hannink, G; Talsma, K W Proc 3rd intermuioul Sympmimn am Laml Smbsidmee, Vodee, 19-25 Matwh 1984 1'885-897. Publ Wallingford: IAHS, 1986 Lowering of the water table due to the reclamation of the Markerwaard polder will increase effective stress in the soil in the North Holland province, and result in subsidence and settlement of buildings. A probabilistic approach has been used to calculate the expected settlement for an area of 500~1 kin. A numerical model has been used to simulate the time dependent fall in water table, and additional calculations have established the relationship between ground surface settlement and settlement of a foundation pile.

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Methnd for esflmathtg ~ damage in subsiding areas Carree, G J; Hulsbergen, J G Pro¢ 3rd Intersmtiomd $ y m ~ d m w oa Lami ,Y~b.~lemee, F e t e , 19-25 Marek 1984 P907-914. Publ WallinRford: IAHS, 1986 Land subsidence is expected in the North Holland province due to reclamation of the Markerwaard polder. The area (500sq kin) was extensively surveyed to determine the numbers and types of buildings present. Relationships were developed between ground movement and subsidence of various types of foundation, and standards for damage were set up for various types of structures. Statistical analysis was used to predict the probability of damage depending on the rate of settlement. After defining damage patterns, reparation costs for the total damage to the area were estimated.

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Three-dime~omd numerical modelling, of surface subsidence ll~ln¢~ by Ule~rgrow~ mining. McNabb, K E CSIRO Division of GeomeckaMcs Teelmieal report N146, 1987, 20P Three dimensional numerical analysis of surface subsidence induced by the total extraction of a longwall panel has been undertaken using finite element and boundary element methods. Profiles are presented for a variety of panel geometries and for isotropic and anisotropic materials. Predictions for a panel of width:length of 5:1 provide results equivalent to 2dimensional analysis when a linear elastic isotropic material model is used. Anisotropic material models are more accurate in reproducing observed subsidence profiles. The need for care in application of numerical models is indicated. Am//- CSIRO Division of Geomechanics, PO Box 54, Mt Waverley, Vic 3149, Australia

© 1988 Pergamon Press plc. Reproduction not permitted