由三軸剪力試驗探討影響崩積併構土力學行為的因素

Abstract

台灣位於歐亞大陸板塊與菲律賓海板塊交界處，造山運動非常顯著。地形陡峭，西部麓山帶大多為較軟弱且膠結性差的沉積物，地理位置屬於亞熱帶氣候，降水豐沛，風化與侵蝕作用劇烈常常會發生山崩及土石流，邊坡破壞後，於邊坡下方堆積非常不均勻的崩積層材料。 由於崩積材料由複雜且不均質的粗顆粒岩塊與細粒的基質組成，岩塊與基質間存在強度及勁度差異，其力學性質不易評估。國內、外的研究結果有限，本研究參考國內外研究方法，針對崩積層鑽探的岩心，以室內三軸試驗及單壓試驗探討崩積併構土的成岩特性、滲透性、剪力強度與破壞模式等。 本研究用掃描儀器計算表面積岩塊含量與體積岩塊含量進行比較，並利用軟岩用三軸試驗系統與土壤三軸系統進行一系列的三軸剪力試驗及單壓試驗，探討不同地區併構土影響力學行為之因素與破壞模式。試驗結果顯示，影響併構土強度的因素有基質的性質、岩塊含量、岩塊大小與分布、含水量與三軸試驗套膜；試體破壞模式發現破壞面為沿著岩塊間發展，並不通過岩塊，分為膨脹型破壞、一組剪裂面破壞、多組剪裂面破壞與複合型破壞。

Taiwan is located at the junction of the Eurasian Plate and the Philippine Sea Plate, and the orogeny is very significant. Most of the Western piedmont blats are distribution of weak and poorly cemented sediments. The geographical location is subtropical climate area. Landslides are often occurs due to Rainfall, weathering and erosion. After the failure of slope, many uneven rock and soil colluvium material accumulates beneath the slope. Because of the complexity and inhomogeneity of the colluvium material that consists of coarse-grained blocks and fine-grained matrix, the strength and stiffness difference between the blocks and the matrix are not easily evaluated by the mechanical properties. Domestic and foreign research results are limited. So, in this study, reference to domestic and foreign research methods, for the core of the collapse of drilling, using triaxial test and uniaxial compression test to discuss the colluvial deposits and the diagenetic process, permeability, shear strength and failure Mode and so on. In this study, the surface block content is calculation by rotated scanning instrument. Investigating a series of triaxial shear tests and uniaxial compression test result were carried out by using triaxial test system. To determinate the influence factors and destruction mode of bimsoil. The test results show that the factors affecting the soil strength include the properties of the matrix, the content of block proportion, the size and distribution of block, the water content and the triaxial test membrane; the failure mode of the sample shows that the failure surface is along the rock mass development, It does not pass through rock blocks; and divided into intumescent damage, a series of shear failure, multiple sets of shear failure and composite damage.