tailieunhanh - SOIL ENGINEERING: TESTING, DESIGN, AND REMEDIATION phần 9

Một số phương pháp thoát nước: thoát nước thoát nước thoát nước thoát nước thoát nước bằng cách bởi bởi bằng cách củng cố lực hấp dẫn hút khô điện thẩm thấu Trong số trên, lợi ích của các nhà tư vấn rõ ràng là trong "hệ thống thoát nước bởi lực hấp dẫn," mặc dù đất hút trên đất mở rộng đã nhận được sự quan tâm. | FIGURE Typical landslide along a highway cut area. drainage patterns deforestation flood excessive rainfall or earthquake-induced flooding can cause massive or localized landslides. Some of the smaller-magnitude landslides can be stabilized by improving drainage. Whenever possible engineers should try to avoid the potential slide risk area. A typical major landslide along a highway in California is shown in Figure . During the location of the Burma Road due to insufficient time for detailed survey a section of road was located in a potential landslide area. After the road 2000 CRC Press LLC was open to traffic a massive slope failure took place. At one time as many as six slides in the cut slope occurred on the same day. Clearing the slides became a major task. At last the engineers gave up and - at great expense - relocated 10 miles of the existing road to a stable area. A granular soil that is looser than the critical density may pass into a state of complete liquefaction if failure starts. Some of these failures may be referred to as mud flow. Such a flow occurs rapidly and the mass that moves may continue to flow to the lower ground a considerable distance away. Flow slides can take place in slopes as flat as 5 to 10 and may result in slides of great magnitude. Almost every stiff clay is weakened by a network of hairline cracks or slickensides. If the spacing of the joints is wide the slope may remain stable even on steep sloping ground during the dry season. However if water is allowed to seep into the cracks the shearing resistance of the weakened clay may become too small to counter the force of gravity and the slide occurs. MAN-MADE SLOPES Man-made slopes are necessary in the construction of highways railroads canals and other projects. In high ground open cuts with adequate slopes will be necessary and on low ground the stability of fill must be considered. Geotechnical engineers seldom pay attention to the design of man-made open cuts and