# Monitoring and Data Analysis in Small-Scale Landslide Physical Model
## 5 Discussion
This would usually need to be measured by another sensor such as a pore pressure transducer, which would take readings when positive pore pressure appeared. Minimum time increment reading for the tensiometers is one minute. For example, TEROS 21 has equilibration time necessary to achieve the balance between water potential of the soil and the ceramic disc. For quick changes in soil materials such as a sand, this time increment could maybe be too much apart, but for materials like silt and clay in which changes take a lot of time, the measurement increment is very frequent. One-minute response time could be a bit of a detriment at the expense of the very high-permeability materials, but for soils with lower permeability, with a presence or entirely silt or clay soil, it is definitely a big advantage and gives realistic and accurate results. The advantages of the use of this type of miniature sensors network, enabled to measure water content and water potentials, are that they measure a wide range of pore pressure values from positive to negative pore pressure, i.e., matric suction, and their readings are in minimal time increments within one minute. Except for a wide spectrum of measuring ranges that can obtain results from sands to clays, other advantages are the miniature dimensions that have very little influence on soil material behavior in a slope model. Water content and water potential sensors related to the acceleration and velocity values measured by MEMS accelerometers would enable a more precise reconstruction of the landslide initiation and landslide development. During infiltration, depending on the rainfall intensity and the hydraulic properties of a soil (i.e., water retention curve and hydraulic conductivity function), the volumetric water content of a soil increases, increasing the pore water pressures and thus potentially eliminating soil suction in a soil profile (Figure 16). In a case of uniformly graded sandy soils, such as the one used in this study, where the soil suction values cannot exceed 10 kPa, the removal of soil suction may reduce the effective stress by a few (e.g., 1-2) kPa. In the case of silty or clayey soils, where reduced water content may cause suction values in the range of a few tens to a few hundreds of kPa, the resulting reduction in effective stress due to reduced matric suction during rain infiltration may be significant. Considering that slope dimensions in small-scale physical models result in relatively low values of confining pressure and the associated frictional strength component, the shear strength component associated with matric suction may be a dominant component of a total available shear strength and thus play an important role in maintaining the stability of a small-scale slope subjected to a rainfall. From the mostly unsaturated slope where no seepage has been established, by infiltration of surface water and an increase in VWC, the matric suction decreases and seepage is established through the layers of the slope after the ground water has been established from the bottom of the slope toward the surface. At the moment when ground water table reached the surface in the foot of the slope, if the boundary conditions allowed it, the soil slope started to slide due to complete loss of the soil strength and ground water seepage that reached the foot of the slope.