Rural settlement development in mountainous areas is the key to eliminating global hunger and poverty. The spatial reconstruction of rural settlements in mountainous areas can promote rural development in mountainous areas. In this study, the Panxi area—a typical mountainous area in China—was chosen as the study area. The driving forces for the spatial reconstruction of rural settlements in mountainous areas were explored from the perspective of peasant households by combining participatory rural appraisal (PRA) with structural equation modeling (SEM). Results showed that: (1) 62.03% of the 266 peasant households included were willing to have spatial reconstruction, indicating that most peasant households in mountainous areas have a very strong intention towards the spatial reconstruction of rural settlements. (2) Infrastructure, medical conditions, living environment, farming culture, and dietary habits significantly influenced the reconstruction intention of peasant households. In contrast, development opportunities, place attachment, language, and living mode each had a slight influence. (3) Geological disasters were the main driving force for the spatial reconstruction of rural settlements in mountainous areas, whilst the driving force of living cohesion was the smallest. This study provides insights for future planning and construction of rural settlements in the Panxi area and spatial reconstruction practices. It has important practical significance for overcoming poverty and realizing rural revitalization in mountainous areas.

Driving Forces for the Spatial Reconstruction of Rural Settlements in Mountainous Areas Based on Structural Equation Models: A Case Study in Western China

Landslides pose significant hazards on the road network of Laos. These landslides frequently block access and occasionally result in the subsidence or loss of the carriageway. Several slope stabilization trials focusing on the use of bioengineering techniques and low-cost engineering measures were implemented in 2007 and 2008. Heavy rains in 2018 caused numerous landslides on the road network and a review was undertaken of the performance of the slope stabilization trial sites implemented ten years earlier. The outcome has proved very positive overall and vindicates the efforts made to understand the causes and mechanisms of the observed slope failures and the ground conditions that pertained. The outcomes of this research have been used to strengthen practice in Laos, and further afield, and to provide a valuable basis for future practice.

https://qjegh.lyellcollection.org/content/qjegh/early/2020/04/15/qjegh2020-064.full.pdf

Performance of slope stabilization trials on the road network of Laos

The approach to ground modelling should be devised to suit the geological and geomorphological challenges that pertain and the context and manner in which the model is to be used. Several case studies are examined where problems experienced during works construction and operation are associated with complex ground conditions and geomorphological outcomes not fully anticipated from the site investigation and ground modelling. Other cases reflect situations where either important existing information was ignored or no apparent consideration was given to the potential for ground engineering problems. Insufficient attention to geomorphology, and especially geomorphological processes, has been the cause of several construction difficulties and continues to pose a significant source of risk in many terrains. The observational and analytical skills of a carefully chosen geo-team will be paramount if these challenges are to be overcome. However, such considerations become largely academic if institutional shortcomings serve to limit or exclude engineering geological assessment in the first place. Thematic collection: This article is part of the Ground models in engineering geology and hydrogeology collection available at: https://www.lyellcollection.org/cc/Ground-models-in-engineering-geology-and-hydrogeology

Getting the basic ground model right in engineering practice

Parts of the Central Cordillera of Luzon are among the most challenging locations on Earth in which to build and maintain transport infrastructure, a situation perhaps most epitomized by the Halsema Highway. Since its original construction in the 1920s, the highway has undergone phased improvement and has become a socio-economic lifeline to the rural communities it serves. Unfortunately, in 1990, continuing road improvement works had to be abandoned owing to the outcome of a 7.8 Ms earthquake and the effects of subsequent typhoon damage. Earthquake reinstatement works were designed in 1998 and constructed between 2001 and 2006. The engineering geological challenge this posed was compounded by the effects of severe typhoon rains during the reconstruction period, requiring continual assessment of changing slope and drainage conditions. Since construction, the road has been affected by several new typhoons including, most notably, Typhoons Pepeng and Ompong in 2009 and 2018 respectively. Field inspections in 2010 and 2018, combined with the interpretation of satellite imagery available in Google Earth, have allowed the performance of the works implemented between 2001 and 2006 to be assessed and the outcome has been largely favourable. Very little of the recorded damage has occurred in the locations of earthquake reinstatement. Instead, several new areas of slope failure and subsequent blockage and damage to the road have developed. Many of these areas can be explained with respect to their underlying engineering geology and geomorphology. However, there are just as many that owe their origin to the pattern of rainfall and runoff arising during the passage of individual and successive typhoons, modified significantly by drainage management practices in the road corridor, where engineering serviceability and land use practices sometimes have conflicting objectives.

Engineering on the precipice: the performance of mountain road rehabilitation in the Central Cordillera of the Philippines

Laos is a mountainous country with a road network that is prone to the impact of landslides. The development and maintenance of the transport sector are seen as imperatives in the country9s socio-economic growth, and landslides pose a potential constraint on this development. This paper describes a landslide vulnerability assessment undertaken for a significant proportion of the country9s mountain road network for maintenance management and investment decision-making purposes. Limited desk study data meant that the focus of the study was on the collection of landslide location and impact data in the field and was able to benefit from the effects of the 2018 wet season during which record rainfalls were recorded in some locations. A simple index of vulnerability was developed and combined with engineering geological observation to yield a composite output that comprised tabular data and maps, along with broad recommendations for risk and engineering management.

Developing a landslide vulnerability assessment for the national road network in Laos

The Central Cordillera of Luzon in the Philippines is home to some of the most complex geology, active plate margin tectonism, heaviest rainfall and steepest terrain in the world. It also hosts a thriving agricultural community that has developed its agrarian, municipal and transport infrastructure in a landscape of marginal stability and extreme geomorphological sensitivity. The village of Pilando occupies a saddle on a prominent ridge where it is crossed by the Halsema Highway. As a result of landslide displacements, both the highway and the village have been subsiding for several decades and many dwellings have had to be abandoned. From topographical survey and visual observation, average rates of settlement vary between c. 0.1 and 0.4 m a−1. The apparent depth and areal extent of ground movement are such that attempts to stabilize the area would be both impracticable and uneconomic. Realignment and relocation are options that might be considered but many adjacent slopes are unstable or have failed in the past and those that have not are highly sensitive to earthworks and drainage disturbance. Unfortunately, there are many areas of the Central Cordillera that are affected by similar slope instability problems. The interpretation of satellite imagery available on Google Earth, supported by geomorphological field observation, can assist in the delineation and assessment of these notably unstable areas for land use planning and slope management purposes.

Jonathan Roy Hart

Papers

Settlements and slides: a large landslide case study from the Central Cordillera of the Philippines