In recent years, several severe disasters due to landslides have occurred in Taiwan. Hence mitigation of landslides becomes especially important. This paper introduces many stabilization methods for landslide repair, which include drainage methods, external stabilization methods as well as internally reinforcing techniques. Among them, the new techniques, especially how they are applied, are described in more details.
This paper presents case histories on the stabilization of 5 highway slopes resting on Cholan Formation of the Western Foothill area in Northern Taiwan. Instabilities caused by the soft sandstone and mudstone interbedded strata, the engineering characteristics and geological structure such as folds are described. Stabilization measures include ground anchor, pile wall, soil buttress, counterweight fill and soil nails were applied in this rock formation. Considerations for design and construction of slopes in sandstone and mudstone formations are summarized for reference of future designs.
The studied case was a cantilever wall with multiple steps originally. A landslide occurred on July, 1992, a flexible geogrid retaining wall was constructed to replace the original rigid one. So far the slope does not fail again for over four years. We hope to introduce the concept of flexible design to engineering sector. It is expected that longer precursory time can be obtained when the retaining structures suffer from an exceeding factor of safety until failure.
This paper describes the investigation and treatment of landslide caused by excavation of a single-track railway tunnel in Southern Taiwan.
According to the results of investigation, there are three landslide areas along the tunnel. Two of them (S1 and S3) are located at portal areas, which were caused by portal excavation and enlarged after heavy rainfall. These landslides are categorized as shallow-depth ones compared to the major landslide zone (S2) located in the middle section of the tunnel. S2 landslide was caused by tunnel excavation and applied significant unbalanced pressure on the sidewall of the tunnel.
The remedial measures applied to these landslide areas are stabilization of the slopes with anchor and rockbolt reinforcements. For S2 landslide, some of the overburden was removed to reduce the unbalanced pressure.
The northern coastal area of Taiwan was prosperous for coal mining during the early stage of development of Taiwan near the turn of the century. Underground coal mining was mainly concentrated in the foothills, and the numerous coal mine adits were left since the coal mining industry gradually exhausted. Following the economic growth and the soaring of slope-land development, the coal mine adits have become a potential hazards for suburban hillside development.
The purpose of this paper is to illustrate the characteristics of coal formations and the coal mining history in Taiwan. The method of survey on the main coal mine adits and two examples of survey on the abandoned coal mine adits are also presented in this paper.
The total length of Kao-Ping-His Bridge is 2.6 kilometers, Which was divided into three construction methods, namely cable stayed, free cantilever and advanced shoring. Besides, the foundations of A1 and P1(abutment and pylon of cable stayed bridge), are diaphragm walls, and other foundations are 1.5m ψconcrete piles cast-in-place with full casing. The foundation of pylon sits on gravel and sand layer of river banks. Because it is in shape of box, there are many corners. What has been mentioned before causes collapses of diaphragm walls. This bridge is the first one with diaphragm walls as foundations in Taiwan.
This article is divided into sections such as geology, excavation equipment, stabilizing solution, unit division and cutting methods, collapse control, the assembling and placing of reinforced cages, underwater concrete pouring, bottom grouting of diaphragm wall, supersonic test of diaphragm wall, counter measure in inclination and sinking of pavement.