台灣西南部地區多屬低塑性粉土質砂，且位處於環太平洋地震帶上，使得山區地層或河流源頭的土層較為鬆動不穩，山區邊坡易形成剪力或張力裂縫，當有地下水、地表逕流入滲，土層裂縫中的土壤顆粒易伴隨水分流失，加速裂縫向下延伸，最終形成一滑動面，進而發生山崩、地滑、土石流等災害。過去對邊坡穩定與防治對策已有諸多研究，但由於崩塌因子判定不易，故有針對國內邊坡崩塌潛能與破壞機制進行更深入探討之必要性。
大規模邊坡滑動面內土壤之行為變化，主要包括土壤於高覆土應力下剪動所造成的顆粒破碎，以及內部逕流沖蝕所造成的顆粒流失兩種狀況。此外，過去對於土壤顆粒破碎之探討相當有限，故本研究以自行開發之「沖蝕直剪試驗儀」，模擬高覆土應力下邊坡滑動面上土壤顆粒破碎之行為，並改變剪動間距，嘗試模擬邊坡滑動面厚度之變化，瞭解滑動面滑動帶形成，對顆粒破碎與土壤強度之關係。
根據試驗結果顯示，剪動間距越小，其破碎量及剪力強度皆越大，當試體細粒料含量越多，剪動間距變化對顆粒破碎量之影響並不顯著。因此，可推測當邊坡滑動初期，滑動面的強度較高，並伴隨大量的顆粒破碎，當邊坡滑動一段距離，滑動面上累積大量的破碎顆粒(細粒料)將形成一俱有厚度之滑動帶，使得滑動面的抗剪強度降低，而顆粒破碎的效應會逐漸減少。

Many soil strata in southwestern Taiwan are dominant in low-plasticity silty sand. Since Taiwan is located in the rim of Circum-Pacific seismic zone, earthquake occurs quite often as a result that the slopes of the low-plasticity silty sand tend to an instable condition. Furthermore, as the groundwater or runoff infiltrate into the tension crack or shear joint of the slope, silty sand is easily flowed out with the water then the crack could be extended downward and be generated a sliding surface finally the landslide or debris flow would be followed. Many efforts has been taken on study of slope stability, however, the factors caused to the landslide were not well defined, it is necessary to investigate more detailed on the potential and mechanism of the landslides.
On the soil behaviors in a large scale landslide, the particle crushing caused by shearing under high confining pressure and particle lost caused by internal erosion are seldom studied in the literatures. In this Study the “Seepage Flow Direct Shear Test Device” is developed to simulate the effect of the particle crushing occurred during the landslide. In addition, thickness of the sliding plane in the landslide is also investigated by changing the shear gap in the device. The relationship between conformation of sliding band and particle crushing with shear strength of soil is established.
Based on the test results, the quantity of the particle crushing and shear strength of the soil increases as the shearing gap decreases. However, the effect of particle crushing is insignificant on the increase of fines content of specimens under different shearing gap. Therefore, it can be reasonably inferred that as the landslide starts to develop, the resistance of the sliding plane is high and with a large amount of particle crusting. Then the particle of soil grain continue crushing and accumulating with the sliding, the amount of particle breakage, i.e. the fines, will form a thick sliding band, which results in decrease of the shear strength of the soil. And the effect of particle crushing becomes insignificant gradually.

1.沈茂松(2000)，實用土壤力學試驗，第七版，臺北：文笙書局。
2.呂偉哲(2011)，「由顆粒間微觀鍵結破壞探討邊坡張力裂縫發展及塊體運動行為」，國立臺灣大學土木工程研究所碩士論文。
3.何志麟(2012)，「低塑性粉土內沖蝕性質之研究─驟變壓力差試驗狀況」，國立成功大學土木工程研究所碩士論文。
4.林昀葦(2006)，「台灣中部地區崩積層抗剪強度之簡易現地試驗」，國立中興大學土木工程研究所碩士論文。
5.林智偉(2006)，「無塑性細料對砂質土壤液化阻抗之研究」，國立成功大學土木工程學研究所碩士論文。
6.林煒喬(2011)，「不同圍壓狀態對低塑性粉土內部沖蝕性質之影響」，國立成功大學土木工程研究所碩士論文。
7.林伯融(2013)，沖蝕直剪試驗儀試驗操作手冊
8.財團法人臺灣營建研究院(2006)，高雄捷運工程橘CO2區段標LUO09潛盾隧道坍陷原因鑑定報告。
9.財團法人臺灣營建研究院(2007)，高雄捷運工程橘線CO1區段標SUO01車站連續壁滲水坍塌事故再分析與對應契約影響之研究報告。
10.陳澤仁(1987)，「砂土顆粒破碎效應與其剪力強度之關係」，國立臺灣大學土木工程研究所碩士論文。
11.許琦(2006)，「剪力盒間隙對礫石抗剪強度之影響」，岩盤工程研討會論文集，第31-40頁。
12.陳俊吉(2013)，「低塑性粉土工程性質之研究」，國立成功大學土木工程研究所博士論文。
13.陳宣佑(2013)，「顆粒組構對低塑性粉土內沖蝕性質影響」，國立成功大學土木工程研究所碩士論文。
14.陳宏銘(2014)，「張力裂縫對邊坡滑動面分佈之影響研究」，淡江大學土木工程研究所碩士論文。
15.鄒永銘(1985)，「端座潤滑對體積膨脹與顆粒破碎之影響」，國立臺灣大學土木工程研究所碩士論文。
16.萬鼎工程公司(2001)，高雄捷運紅橘線路網補充地質調查工程地質調查報告書。
17.廖元憶(2005)，「台灣西南沿海高細粒料含量砂土的探討」，國立成功大學土木工程研究所碩士論文。
18.廖泓韻(2013)，「以微觀角度探討顆粒狀材料在直剪試驗下行為」，國立中央大學土木工程研究所碩士論文。
19.劉全修(2008)，「台灣中南部粉土質細砂的壓縮性」，國立交通大學土木工程研究所碩士論文。
20.蕭吉良(2010)，「低塑性粉土內部沖蝕性質之研究」，國立成功大學土木工程研究所碩士論文。
21.謝明紋(2000)，「砂性土壤與地工止水膜直剪試驗尺寸與承壓效應之研究」，國立屏東科技大學土木工程研究所碩士論文。
22.蘇聖惟(1999)，「砂土排水與不排水受剪行為之比較」，國立臺灣大學土木工程研究所碩士論文。
23.ASTM D452M-91 (2013), Standard Test Method for Sieve Analysis of Surfacing for Asphalt Roofing Products.
24.ASTM D3080M-11 (2012), Standard Test Method for Direct Shear Test of Soils Under Consolidated Drained Conditions.
25.Bishop, A. W. (1966), “The Strength of Soils as Engineering Materials, ” Geotechnique, Vol. 16, No. 2, pp. 91-130.
26.Das, B. M. (2010), Principles of geotechnical engineering – SI version, 7th edition, Cengage Learning, USA.
27.Feda J. (1973), Stability of natural slopes, 8th International Conference Soil Mechechanics and Foundation Engineering, Oral discussion, Session 6.
28.Head, K. H. (1982), Manual of Laboratory Testing, Halsted Press , Vol. 2, pp.554-559.
29.Hardin, B. O. (1985), “Crushing of Soil Particles, ” Journal of the Geotechnical Engineering Division, ASCE, Vol. 3,No. 10, pp. 1177-1192.
30.Ingold, T. S. (1984),“A Laboratory Investigation of Soil-Geotextile Friction, ” Ground Engineering, November, pp. 21-28.
31.Ishihara, K. (2013), personal discussion.
32.Kim B. S. (2012), “Effect of Opening on the Shear Behavior of Granular Materials in Direct Shear Test, ” Journal of Civil Engineering, KSCE, Vol. 16, No. 7, pp. 1132-1142.
33.Leslie, D. D. (1963), “Large Scale Triaxial Tests on Gravelly Soils, ” Proceedings of the 2nd Panamerican Conference on Soil Mechanics and Foundation Engineering, Brazil, Vol. 1, pp. 181-202.
34.Lee, K. L., and Farhoomand, I. (1967), “Compressibility and Crushing of Granular Soil, ” Canadian Geotechnical Journal, Vol. 4, No. 1, Feb., pp. 68-86.
35.Lee, K. L., and Seed, H. B. (1967), “Drained Strength Characteristics of Sand, ” Journal of the Soil Mechanics and Foundations Division, ASCE, Vol. 93, No. SM6, Nov., pp. 117-141.
36.Lee, K. L., Seed, H. B., and Dunlop, P. (1967), “Effect of Moisture on the Strength of a Clean Sand, ” Journal of the Soil Mechanics and Foundations Division, ASCE, Vol. 93, No. SM6, Nov., pp. 17-40.
37.Leslie, D. D. (1975), “Shear Strength of Rockfill, ” Physical Properties Engineering Study No. 526, South Pacific Division, Corps of Engineers Laboratory, Sausalito, Calif., Oct., p. 124.
38.Lambe, T. W. and Whitman R. V. (1979), Soil Mechanics SI Version, John Wiley & Sons, New York.
39.Lambe, T. W. (1981), Soil Testing for Engineers, Wiley, pp. 88-97.
40.Marsal, R. J. (1965), “Discussion of Shear Strength, ” Proceedings of the 6th International Conference on Soil Mechanics and Foundation Engineering, Montreal, Vol. 3, pp. 310-316.
41.Marsal, R. J. (1969), “Mechanical Properties of Rockfill and Gravel Materials, ” Proceedings of the 7th International Conference on Soil Mechanics and Foundation Engineers, Vol.3, pp.499-506.
42.Miura, N., Murata, H. and Harada, A. (1983), “Effect of Water on the Shear Characteristics of Sandy Soils Consisted of Breakable Particles, ” Transactions of the Japanese Society of Civil Engineering, Vol. 15, pp. 377-380.
43.Rowe, P. W. (1962), “The Stress-Dilatancy Relation for Static Equilibrium of an Assembly of Particles in Contact, ” Proceedings of the Royal Society, London, England, Series A, Vol. 269, pp. 500-527.
44.Varnes, D. J. (1978), Slope movement types and process: In landslides.
45.Yamamuro, J. A. and Covert K. M. (1998), “Steady-State Concepts and Static Liquefaction of Silty Sands, ” Journal of Geotechnical and environmental Engineering, Vol.124, pp. 868-878.
46.Yamamuro, J. A. and Covert K. M. (2001), “Monotonic and Cyclic Liquefaction of Very Loose Sands with High Silt Content, ” Journal of Geotechnical and environmental Engineering, Vol.127, No.4, pp. 314-324.