Maintenance problem for infrastructures such as bridge, road, airport, etc., attracts keen interest in modern Japan. We have to cope with repair and maintenance for infrastructures with limited financial resources. In airport pavements, repair works are restricted by daily flight operation, so that efficient maintenance planning is required. In this paper, we try to model deterioration of an existing airport runway, which is composed of 100 units. PRI (Pavement Rehabilitation Index) for each unit is obtained by 3 to 8 times of inspection during around 28 years. PRI is an index to provide an objective evaluation of pavement surface condition, with criteria determined for judging the need for rehabilitation work on runway, taxiway, and apron pavements. Many researches and practitioners use PRI for airport pavement maintenance in Japan. The spatial distribution of deterioration in airfield pavement is not discussed in many previous studies. This study discusses deterioration curve for each unit and feature of spatial distribution. The distribution of deterioration based on PRI and the probability of exceedance of each PRI criteria in future are estimated by the proposed method.

Various in situ testing techniques are commonly employed to obtain geotechnical parameters for use in analyses and design. Some of the more popular field tests include standard penetration tests (SPTs), cone penetration tests (CPTs) and Swedish weight sounding (SWS). SPT and CPT are commonly preferred for large-scale projects, but they are expensive when implemented for small-scale constructions. SWS is highly portable and economical but poor in classifying soils. The screw driving sounding (SDS) test, which has been recently developed in Japan, is an improved version of SWS and can measure more parameters, including the required torque, load, speed of penetration and rod friction, and thereby provides a robust way of characterising soil stratigraphy. It is cost efficient and uses a machine-driven and portable device, making it suitable for testing in confined areas. Moreover, with a testing depth of 10–15 m, it is ideal for characterising shallow deposits. In this paper, the SDS test is introduced and the results of its application to various New Zealand sites are discussed. Moreover, a number of correlations between SDS parameters and CPT/SPT data are presented. The results prove that SDS can be an effective alternative for soil characterisation, particularly in residential areas and roading projects.

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This paper discusses methods for realistic simulation of slope failure owing to heavy precipitation in a centrifuge. A rain simulator was developed to provide precipitation that satisfies the conditions in a centrifuge so that the impact pressure on the ground surface in the centrifuge (pm) was reduced to the same level in the prototype (pp). Pneumatic spray nozzles, producing fine droplets with a mean diameter of 20 µm, yield large precipitation intensity of 1500 mm/h on the model at 50g. Accordingly, the model precipitation intensity (rm) was provided by n times the corresponding prototype precipitation intensity (rp). Several sets of centrifuge tests were conducted to observe the progress of failure in the shallow section of the slope. Heavy precipitation induces an increase in the saturation of the soil from the surface. Flow failure was observed repeatedly in the shallow section through progress of the wetting front. In addition, experiments using different viscosity used in the liquid for precipitations were carried out to compare the types of failure. Larger failure by precipitation of the viscous liquid was observed than that of water even when equivalent permeability conditions are maintained. This paper also introduces a method of measuring shear deformation in the shallow section by bending strains, allowing monitoring of the progress of failure.

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