scholarly journals Origin and assessment of deep groundwater inflow in the Ca' Lita landslide using hydrochemistry and in situ monitoring

2012 ◽  
Vol 9 (6) ◽  
pp. 7699-7738
Author(s):  
F. Cervi ◽  
F. Ronchetti ◽  
G. Martinelli ◽  
T. A. Bogaard ◽  
A. Corsini
Keyword(s):  
Deep Water ◽  
Major Ions ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Slope Instability ◽  
In Situ Monitoring ◽  
Water Inflow ◽  
Groundwater Levels ◽  
Italian Apennines

Abstract. Changes in soil water content, groundwater flow and a rise in pore water pressure are well-known causal or triggering factors for hillslope instability. Rainfall and snowmelt are generally assumed as the only sources of groundwater recharge. This assumption neglects the role of deep water inflow in highly tectonized areas, a factor that can influence long-term pore-pressure regimes and play a role on local slope instability. This paper aims to assess the origin of groundwater in the Ca' Lita landslide (northern Italian Apennines) and to qualify and quantify the aliquot attributable to deep water inflow. The research is essentially based on in situ monitoring and hydrochemical analyses. It involved 5 yr of continuous monitoring of groundwater levels, electrical conductivity and temperature, and with groundwater sampling followed by determination of major ions, tracers (such as Boron and Strontium), and isotopes (Oxygen, Deuterium, Tritium). Leaching experiments on soil samples and water recharge estimation were also carried out. Results show that the groundwater balance in the Ca' Lita landslide must take into account an inflow of highly mineralized Na-SO4 water (more than 9500 μS cm−1) with non-negligible amounts of Chloride (up to 800 mg l−1). The deep water inflow recharges the aquifer hosted in the bedrock underlying the sliding surface (at a rate of about 7800–17 500 m3 yr−1). It also partly recharges the landslide body, where the hydrochemical imprint of deep water mixed with rainfall and snowmelt water was observed. This points to a probable influence of deep water inflow on the mobility of the Ca' Lita landslide, a finding that could be applicable to other large landslides occurring in highly tectonized areas in the northern Apennines or in other mountain chains.

scholarly journals Origin and assessment of deep groundwater inflow in the Ca' Lita landslide using hydrochemistry and in situ monitoring

2012 ◽  
Vol 16 (11) ◽  
pp. 4205-4221 ◽  
Author(s):  
F. Cervi ◽  
F. Ronchetti ◽  
G. Martinelli ◽  
T. A. Bogaard ◽  
A. Corsini
Keyword(s):  
Groundwater Flow ◽  
Deep Water ◽  
Major Ions ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Slope Instability ◽  
In Situ Monitoring ◽  
Water Inflow ◽  
Groundwater Levels

Abstract. Changes in soil water content, groundwater flow and a rise in pore water pressure are well-known causal or triggering factors for hillslope instability. Rainfall and snowmelt are generally assumed as the main sources of groundwater recharge. This assumption neglects the role of deep water inflow in highly tectonized areas, a factor that can influence long-term pore-pressure regimes and play a role on local slope instability. This paper aims to assess the origin of groundwater in the Ca' Lita landslide (northern Italian Apennines) and to qualify and quantify the aliquot attributable to deep water inflow. The research is essentially based on in situ monitoring and hydrochemical analyses. It involved 5 yr of continuous monitoring of groundwater levels, electrical conductivity and temperature and with groundwater sampling followed by determination of major ions (Na+, K+, Mg2+, Ca2+, Cl−, HCO3−, SO42−), tracers (such as Btot and Sr2+), and isotopes (δ18O, δ2H and 3H). Leaching experiments on soil samples, hydrochemical modelling and water recharge estimation were also carried out. Results show that the groundwater balance in the Ca' Lita landslide must take into account an inflow of deep and highly mineralised Na-SO4 water (more than 9500 μS cm−1) with non-negligible amounts of Cl− (up to 800 mg l−1). The chemical and isotopic fingerprint of this water points to oilfield water hosted at large depths in the Apennine chain and that uprises through a regional fault line crossing the landslide area. It recharges the aquifer hosted in the bedrock underlying the sliding surface (at a rate of about 49 000–85 700 m3 yr−1) and it also partly recharges the landslide body. In both the aquifers, the hydrochemical imprint of deep water mixed with rainfall and snowmelt water was observed. This indicates a probable influence of deep water inflow on the mobility of the Ca' Lita landslide, a finding that could be applicable to other large landslides occurring in highly tectonized areas in the northern Apennines or in other mountain chains. The paper demonstrates that hydrochemistry should, therefore, be considered as a valuable investigation method to define hydrogeological limits and the groundwater sources in hillslope and to assess groundwater flow patterns in deep-seated landslides.

scholarly journals Effect of groundwater fluctuation, construction, and retaining system on slope stability of Avas Hill in Hungary

2021 ◽  
Vol 13 (1) ◽  
pp. 1139-1157
Author(s):  
Eslam M. Hemid ◽  
Tamás Kántor ◽  
Ahmed A. Tamma ◽  
Mostafa A. Masoud
Keyword(s):  
Slope Stability ◽  
Groundwater Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Slope Instability ◽  
Negative Effects ◽  
Destructive Effect ◽  
Groundwater Levels ◽  
Groundwater Level Fluctuations ◽  
The Church

Abstract Landslides are one of the natural hazards, which have significant negative effects on both humans and the environment. Thus, slope stability analyses and stabilization processes are necessary to obviate or mitigate landslides. In this study, the effect of groundwater level fluctuations and the construction of a building (i.e., a recently built church) on slope stability was investigated on the eastern slope of the Avas Hill, at Miskolc, in Northeast Hungary. Soil movements and groundwater levels were monitored and geological and slope stability models were constructed. Furthermore, the possibility of constructing a retaining system was evaluated to minimize the detrimental effects of both groundwater level fluctuations and the construction of the church. The findings showed that the fluctuation in groundwater levels had a destructive effect on slope stability due to pore-water pressure, which decreased the soil strength of the slope and slope stability. On the other hand, the church added an external load onto the underlying soil leading to an increase in slope instability. Hence, we suggested constructing retaining structures such as gravity retaining walls to increase the soil shear strength and enhance slope stability in the long term.

The Test Study to the Changes of Excess Pore Water Pressure during Precast Pile Construction

2012 ◽  
Vol 193-194 ◽  
pp. 1010-1013
Author(s):  
Shu Qing Zhao
Keyword(s):  
Pore Water ◽  
Clayey Soil ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Excess Pore Pressure ◽  
Soil Pressure ◽  
Excess Pore Water Pressure ◽  
Test Study ◽  
Excess Pore

The construct to precast pile in thick clayey soil can cause the accumulation of excess pore water pressure. The high excess pore pressure can make soil, buildings and pipes surrounded have large deflection, even make them injured. Combining with actual projects, this paper presents an in-situ model test on the changes of excess pore water pressure caused by precast pile construct. It is found that the radius of influence range for single pile driven is about 15m，the excess pore water pressure can reach or even exceed the above effective soil pressure, and there are two relatively stable stages.

A Heating Experiment in the Argillites in the Meuse/Haute-Marne Underground Research Laboratory

2007 ◽  
Author(s):  
Yannick Wileveau ◽  
Kun Su ◽  
Mehdi Ghoreychi
Keyword(s):  
Research Laboratory ◽  
Linear Thermal Expansion Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Linear Thermal Expansion ◽  
General Description ◽  
In Situ Experiment ◽  
Heating And Cooling ◽  
Underground Research Laboratory

A heating experiment named TER is being conducted with the objectives to identify the thermal properties, as well as to enhance the knowledge on THM processes in the Callovo-Oxfordian clay at the Meuse/Haute Marne Underground Research Laboratory (France). The in situ experiment has being switched on from early 2006. The heater, 3 m length, is designed to inject the power in the undisturbed zone at 6 m from the gallery wall. A heater packer is inflated in a metallic tubing. During the experiment, numerous sensors are emplaced in the surrounding rock and are experienced to monitor the evolution in temperature, pore-water pressure and deformation. The models and numerical codes applied should be validated by comparing the modeling results with the measurements. In parallel, some lab testing have been achieved in order to compare the results given with two different scales (cm up to meter scale). In this paper, we present a general description of the TER experiment with installation of the heater equipment and the surrounding instrumentation. Details of the in situ measurements of temperature, pore-pressure and strain evolutions are given for the several heating and cooling phases. The thermal conductivity and some predominant parameters in THM processes (as linear thermal expansion coefficient and permeability) will be discussed.

Study on Slope Instability Disciplinarian on the Condition of Rainfall

2013 ◽  
Vol 353-356 ◽  
pp. 654-658
Author(s):  
Nan Tong Zhang ◽  
Xiao Chun Zhang ◽  
Hua Rong Wang ◽  
Chen Yan
Keyword(s):  
Slope Stability ◽  
Tensile Stress ◽  
Rainfall Intensity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Road Construction ◽  
Slope Instability ◽  
Slope Surface ◽  
Large Area ◽  
Break Zone

Slope stability is one of the problems of road construction which should be faced with and solve. Rainfall can reduce the shear strength of slope soil and raise the underground water level which can lead to increase slope soil pore water pressure. The influence of rainfall infiltration on slop is mainly to change the slope seepage field, increase dynamic and hydrostatic water load on the slope soil and decrease of soil shear parameters. More abundant rainfall of typhoon area could make the road slope stability more fragile. Based on Matoushan Mountain along 104 state roads in Taizhou city, Zhejiang province, slope instability disciplinarian on the condition of rainfall is studied using the method of numerical simulation in this paper. As the results, when the rainfall intensity was 0.006 m/h and continuous rain was in 24 hours, the slope surface compressive stress tends to zero which began to appear tensile stress area on the condition of self-weight. And when the rainfall intensity was 0.01 m/h and continuous rain was in 24 hours, the large area of the slope surface was tensile stress area which means to appear break zone in slope surface and likely to landslide at the same time.

In Situ Study on Soil Disturbance Induced by Shield Tunneling in Tianjin

2013 ◽  
Vol 368-370 ◽  
pp. 1674-1677
Author(s):  
Yong Hua Cao ◽  
Xiao Qiang Kou
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Disturbance ◽  
Ground Settlement ◽  
Soil Pressure ◽  
Shield Tunneling ◽  
Tunnel Face ◽  
Tunneling Process

In urban environment, the soil disturbance induced by shield tunneling can be sensitive because it can cause deformation of the ground and damage the near structure. To study this disturbance in the construction process of Tianjin metro line No.3, in-situ monitoring of pore water pressure, soil pressure and ground settlement were conducted. The pore water pressure was monitored for the soil around the tunnel. The soil pressure was monitored for the soil around the tunnel and on the tunnel face. It was revealed that the pore water pressure and soil pressure changed twice in the tunneling process and these changes were induced by cutting face and grouting at the shield tail. The soil pressure on the tunnel face reached its maximal value when the distance between the cutting face and the sensor elements was around the diameter of the tunnel. Ground settlement developed in the tunneling process. The shape of ultimate settlement trough is closed to the one obtained by Pecks method.

scholarly journals In situ measurements of till deformation and water pressure

2006 ◽  
Vol 52 (177) ◽  
pp. 175-182 ◽  
Author(s):  
Martin Truffer ◽  
William D. Harrison
Keyword(s):  
Pore Water ◽  
Pressure Transducer ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Spatial Homogeneity ◽  
Early Season ◽  
Surface Motion ◽  
Speed Up ◽  
Tilt Sensor

AbstractA newly developed hammer was used to insert two autonomous probes 0.8 m and 2.1 m into clast-rich subglacial till under Black Rapids Glacier, Alaska, USA. Both probes were instrumented with a dual-axis tilt sensor and a pore-water pressure transducer. The data are compared to a 75 day record of surface velocities. Till deformation at depth was found to be highly seasonal: it is significant during an early-season speed-up event, but during long periods thereafter measured till deformation rates are negligible. Both tilt records show rotation around the probe axis, which indicates a change in tilt direction of about 30°. The tilt records are very similar, suggesting spatial homogeneity on the scale of the probe separation (4 m horizontal and 3.3 m vertical). There is evidence that during much of the year sliding of ice over till or deformation of a thin till layer (<20 cm) accounts for at least two-thirds of total basal motion. Basal motion accounts for 50–70% of the total surface motion. The inferred amount of ice–till sliding is larger than that found at the same location in a previous study, when surface velocities were about 10% lower. We suggest that variations in ice–till coupling account for the observed variations in mean annual speed.

Further Study on the Application of Self-Boring Pressuremeter Test in Clays

2011 ◽  
Vol 243-249 ◽  
pp. 2752-2758
Author(s):  
Quan Cao ◽  
Hong Chen
Keyword(s):  
Experimental Investigation ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Small Strain ◽  
Linear Analysis ◽  
The Self ◽  
Geotechnical Investigation ◽  
Pressuremeter Test ◽  
In Situ Method

The self-boring pressuremeter test has potential advantages over the conventional in situ method in the geotechnical investigation. It not only provides fundamental soil properties for the designer, but also plays more important role in the geotechnical analysis. With help of Cambridge self-boring model pressuremeter tests, some new application are studied in this paper as following: (1) Analysis of stress paths in clays adjacent to the cavity wall during self-boring pressuremeter test; (2) Experimental investigation on stiffness of soils at small strain under non-linear analysis; and (3) Study on magnitude of the changes in pore-water pressure of clays, which will help to enlarge the application of self-boring pressuremeter test in geotechnical engineering.

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