No abstract

In June 2008, the Shenzhen landfill slope failed. This case is used as an example to study the deformation characteristics and failure mode of a slope induced by high water levels. An integrated monitoring system, including water level gauges, electronic total stations, and inclinometers, was used to monitor the slope failure process. The field measurements suggest that the landfill landslide was caused by a deep slip along the weak interface of the composite liner system at the base of the landfill. The high water level is considered to be the main factor that caused this failure. To calculate the relative interface shear displacements in the geosynthetic multilayer liner system, a series of numerical direct shear tests were carried out. Based on the numerical results, the composite lining system simplified and the centrifuge modeling technique was used to quantitatively evaluate the effect of water levels on landfill instability.

A new sand preparation method is developed for physical model testing. This method is especially suitable to create fully saturated samples, since the construction of the sample and densification afterwards is performed under saturated conditions. In this way the tedious saturation of a sample made from dry sand (for example when using the dry raining method) and the drying of the sand after the test are avoided. The new method is based on the low velocity of free falling sand grains in water to create a loose sample that can be compacted homogeneously afterwards to the desired density by means of small impacts. The paper presents the practical information, possibilities and limitations of the procedure. that in large sand models the bulk density is the same as the local measured densities taken in 50 positions of the sand body. This paper will describe the further developed method for sample preparation in more detail. THE DRIZZLE METHODThe method described in this paper is based on the low velocity of free falling sand grains in water. Section 2.1 describes the method in detail. Section 2.2 shows the calculation of the dry weight of the model and 2.3 has a detailed description on the compaction procedures. Section 2.4 gives a short insight on how this method works with viscous fluids and Section 2.5 gives some remarks on the procedure. The drizzle method for sand sample preparationA cylindrical container, the storage cell, was used to store the sand-water mixture. The sand-water mixture was obtained by using de-aired water and pouring the desired sand carefully into the water to avoid air-inclusions. The sand model cell is the container used for preparing the sand model. After weighing the empty sample cell, it is filled with de-aired water. Now there are two cells: the storage cell with the mixture and the sand model cell. It is important that the water contains no air because this will influence the permeability of the sand model and the compressibility of the water. A submersible pump is placed in the storage cell containing the prepared sand-water mixture. The mixture is pumped into the prepared sand modelcell using synthetic pipes filled with de-aired water,

A model waste mixing with kaolin, sand, and peat was developed. The physical properties of the waste were compared with the real municipal solid waste (MSW). The influence of unit weight on compression factor, shear strength, and saturated hydraulic conductivity was acquired. In addition, the homogeneous of the soil model was detected using the IWHR 450g-ton centrifuge and the newly developed centrifuge-robot.

Abstract. Seismic response of municipal solid waste (MSW) landfill under horizontal and vertical earthquakes has been investigated by dynamic centrifuge testing. The MSW was modelled by mechanically representative model waste. The acceleration response at various depths were recorded and used to investigate the amplification characteristics of a MSW landfill. Vertical settlement was also measured during the shaking event. Post-test observations were compared to the realistic damage that occurs in a landfill under earthquake loading. The results also provide the data for validating the analytical methods of the seismic response of MSW landfill.