工程地質(zhì)學(xué) 巖質(zhì)邊坡穩(wěn)定分析ppt課件

1、The Vaiont Landslide in the Dolomites(The Dolomites are a mountain range in Northern Italy)This map shows the scale of the landslide, which slopped the contents of the reservoir over the dam and killed more than 2000 people in Longarone and the adjoining communities This is a view of the landslide f

2、rom upstream. 地質(zhì) 在三峽調(diào)查發(fā)現(xiàn)，只需地勢(shì)平坦些的地方，多半有居民和城鎮(zhèn)，而這些平地十之八九是古滑坡，如秭歸老縣城、新灘鎮(zhèn)、云陽(yáng)老縣城、云安鎮(zhèn)等等。在這些古滑坡上，人們繁衍生息，耕種收獲。古代三峽人口少，沒(méi)有大規(guī)模的開(kāi)挖和高樓大廈的建立，所以雖然是建城在許多滑坡體上，人與自然倒能上千年相安無(wú)事。Rockslide at Yosemite National Park, California kills one, injures 4尾縱剖面開(kāi)挖后破壞接近度圖7. 不穩(wěn)定邊坡的防治措施不穩(wěn)定邊坡的防治措施平整坡面以免坑洼地積水平整坡面以免坑洼地積水外圍挖溝槽以阻斷地表水流向坡體外圍挖

3、溝槽以阻斷地表水流向坡體坡體上修筑排水溝坡體上修筑排水溝防地表防地表水入滲水入滲Surface Drainage on a slope on the road into Runswick Bay, a coastal village in Yorkshire, EnglandIn the Henllys landslide in South Wales trench drains have been dug in front of the landslip, so that it will slide over the top, and be drained from underneath.

4、Drains are installed in near-horizontal boreholes under a tip of urban refuse which was sliding downhill near Ancona, Italy. This diagram shows a coastal landslide with several systems of drainage Drains are installed in near-horizontal boreholes from shafts in a coastal landslide at Herne Bay, Kent

5、. Drains are installed in a variety of ways to stabilize slopes. 固坡網(wǎng)系統(tǒng)是防治淺層邊坡失穩(wěn)的輕型開(kāi)放式護(hù)固坡網(wǎng)系統(tǒng)是防治淺層邊坡失穩(wěn)的輕型開(kāi)放式護(hù)坡系統(tǒng)。它主要以輕型金屬網(wǎng)緊固有潛在擴(kuò)離落石危坡系統(tǒng)。它主要以輕型金屬網(wǎng)緊固有潛在擴(kuò)離落石危險(xiǎn)的坡面，其縱橫交錯(cuò)的險(xiǎn)的坡面，其縱橫交錯(cuò)的16張拉強(qiáng)與張拉強(qiáng)與4.54.5m實(shí)實(shí)踐施工中可根據(jù)地形條件在踐施工中可根據(jù)地形條件在4.2m-4.8m間作適當(dāng)調(diào)整間作適當(dāng)調(diào)整選用正方形方式布置的錨桿相結(jié)合，張拉繩構(gòu)成的選用正方形方式布置的錨桿相結(jié)合，張拉繩構(gòu)成的每個(gè)每個(gè)4.5m X4.5m網(wǎng)格內(nèi)

6、鋪設(shè)一張網(wǎng)格內(nèi)鋪設(shè)一張4mX4m的的RN/08/400型鋼繩網(wǎng)，每張鋼繩網(wǎng)與周圍張拉繩間用縫合繩縫合型鋼繩網(wǎng)，每張鋼繩網(wǎng)與周圍張拉繩間用縫合繩縫合結(jié)合并進(jìn)展預(yù)張拉，該預(yù)張拉工藝能使該系統(tǒng)對(duì)坡面結(jié)合并進(jìn)展預(yù)張拉，該預(yù)張拉工藝能使該系統(tǒng)對(duì)坡面施以一定的法向預(yù)緊壓力，從而提高危巖體的穩(wěn)定性，施以一定的法向預(yù)緊壓力，從而提高危巖體的穩(wěn)定性，阻止落石的發(fā)生。同時(shí)，這種開(kāi)放式的防護(hù)方式不會(huì)阻止落石的發(fā)生。同時(shí)，這種開(kāi)放式的防護(hù)方式不會(huì)影響地下水的正常排泄，并且給邊坡的生態(tài)治理提供影響地下水的正常排泄，并且給邊坡的生態(tài)治理提供了先決條件。了先決條件。 導(dǎo)石棚系統(tǒng)根本原理與棚洞一樣，但該系統(tǒng)采用的是高強(qiáng)熱鍍鋅

7、鋼絲繩網(wǎng)、導(dǎo)向安裝和防停積安裝等，可將路塹邊坡上的落石平安有效的引導(dǎo)到指定區(qū)域。由于該系統(tǒng)安裝簡(jiǎn)易且工期短，是已建成通車的公路或鐵路邊坡防治擴(kuò)離-落石災(zāi)禍的有效方法。 Gros Ventre Landslide Wyoming Traits:largest historic slide in U. S. June 23rd, 1925. 40 million metric tons. followed heavy rains and snow melt. formed 40-60 meter deep lake. beds dipping parallel to slope. ranch de

8、stroyed by rising lake. 1927 break out flood. View from Grand Teton mountains across valley to E to Gros Ventre Range and large flake scar on mountain side.Upper part of slide showing where basal slip surface at bottom of Tensleep sandstone (on top of Amsden Formation clay beds) is exposed. Note int

9、act sliver with trees half way down bare scarp.View from interior of hummocky toe to other side of valley where Tensleep sandstone rode up and against in place Chugwater red clastics.View from head scarp scar with snow to translational slide block in middle to hummocky toe at base.Creep is the unnot

10、iced slow movement of unconsolidated soils downslope. It is commonly seen as curved tree trunks as in the above phote. Important to look for when buying real estate but not life-threatening. An earth flow near Interstate Highway 70, Ellsworth County. The head is the upslope portion of the landslide.

11、 The scarp, the steeply inclined failure surface with exposed soil and rock, marks the top of a landslide. The toe is the downslope portion of the landslide. A mound of soil called a lobe marks the toe of the landslide. RECOGNITION OF AREAS OF POTENTIAL SLOPE FAILURE (25)I Main Topics A Motivation B

12、 Signs of slope instability anaheim-landslide/I I Motivation A Most landslides (or potential slides) can be recognized or predicted if the proper investigations are performed in advance. B Except for small slides, slides typically cost far less to prevent than to fix (An ounce of revention is worth

13、a pond of cure.). C Massive slides may cost many times the cost of the desired facility; they should be avoided.III Signs of past slope instability (focus on topography and hydrology) A Review of maps (Figs. 4.5, 3.9 in SR 176) B Review of aerial photos & remote sensing imagery in SR 176 1 Hummo

14、cky topography /Publications/pic13/pic13_2.html a Oblique aerial photos: Figs. 2.19, 2,22, 2.23, 2.28, 2.33 b Stereophotos: Figs. 3.14, 3.26, 3.31 2 Arcuate fractures and old scarps or scars anaheim-landslide/features.htm a Oblique aerial photos: Figs. 2.19, 3.40, b Stereophotos: Figs.

15、3.5, 3.7, 3.14, 3.19, 3.20, 3.24 3 Areas of anomalous vegetation (seasonal photos useful) a Oblique aerial photos: Plate 3.3 a Stereophotos: Plates 3.1, 3.2 4 Areas of seepage: Vertical infrared imagery: Fig. 3.35 5 Sand flows and talus (Figs. 3.25, 3.30 ) C Features to examine in field reconnaissan

16、ce 1 Ground cracks (Fig 4.2 in SR 176) 2 Closed hillside depressions 3 Phreatophytes and seeps 4 Patched or hummocky roads 5 Tilted walls, trees, and fencesSurface signs of soil creep. Leaning power and telephone pole, fences and gravestones, and trees bending first downslope before growing straight

17、 up may provide evide of soil creep.The mechanics of soil creep. Individual soil or rock particles are raised at right angles to the slope by swelling or expansion and then settle vertically downward during compaction or contraction. The net result is slow downslope creep.EARTHFLOW : Soil and other surface materials move downslope as a viscous flow.SLUMP : a type of rotational slide.BLOCK SLIDE : The sl