土工合成材料加固擋土墻(Geosynthetic Reinforced Retaining Wall)
1 引言
在《土釘支護(hù)的邊坡穩(wěn)定性(Stability of Slope Reinforced with Soil Nails)》中曾經(jīng)提到，HYRCAN目前提供了5種支護(hù)型式：End Anchored, Grouted Tieback, Soil Nail, GeoTextile, Pile。這個(gè)筆記討論了使用GeoTextile支護(hù)擋土墻的計(jì)算過(guò)程。
GeoTextile支護(hù)類型可用于模擬各種類型的邊坡加固，例如網(wǎng)(meshes)、網(wǎng)格(grids)、條帶(strips)等。這類支撐系統(tǒng)通常被稱作土工織物或土工布、土工格柵、土工合成材料等。
2 問(wèn)題陳述
該擋土墻擬使用9m長(zhǎng)的土工合成材料進(jìn)行支護(hù)，地基土有兩層，上層為回填土(Backfill), 下層為冰川沉積土(Glacial till, 加拿大北部地區(qū)典型的土層)，支護(hù)區(qū)域單獨(dú)劃為一種材料。
地層的物理力學(xué)屬性如下所示。
3 HYRCAN計(jì)算
根據(jù)上面的問(wèn)題陳述依次設(shè)置外部邊界，材料邊界，材料屬性，指定屬性。
set("numSlice",50,"Method","GLE/M-P","on","Method","JanbuSim","on","Method","Spencer","on")extboundary(-23,-5,-14,-4.5,-12,-5.5,-1,0,0,0,0,8.3,9.1,8.3,16,7.5,19.5,6,24,6.5,24,-15,-23,-15,-23,-5)matboundary(-23,-7.5,-7,-7.5,-4.5,-8,-1.5,-7,24,-7)matboundary(0,0,9.1,0,9.1,8.3)definemat("ground","matID",1,"matName","Backfill","uw",21.7,"friction",33)definemat("ground","matID",2,"matName","Wall","uw",20.4,"cohesion",0,"friction",41)definemat("ground","matID",3,"matName","Till","cohesion",2,"friction",54)assignsoilmat("matid",1,"atpoint",5.73128,-4.02114)assignsoilmat("matid",2,"atpoint",6.28592,2.26478)assignsoilmat("matid",3,"atpoint",4.80688,-12.5256)
接下來(lái)增加支護(hù)。使用"屬性(Properties)->定義支護(hù)(Define Support)"菜單打開支護(hù)屬性對(duì)話框。目前程序有5種支護(hù)方式可以選擇，在本例中，支護(hù)類型選擇土工材料(Geotexile)，輸入下圖所示的參數(shù)。
Geotexile分三種類型，區(qū)別在于抗拉強(qiáng)度的不同。施力方式選擇“被動(dòng)",力的方向選擇"平行于加固(Parallel to Reinforcement)",錨固類型選擇"Slope Face"。
definemat("support","matID",1,"supportType","GeoTextile","matName","Type 1","forceApp","passive","stripTensile",111,"stripAdhesion",0,"stripFricAngle",41)definemat("support","matID",2,"supportType","GeoTextile","matName","Type 2","forceApp","passive","stripTensile",71,"stripAdhesion",0,"stripFricAngle",41)definemat("support","matID",3,"supportType","GeoTextile","matName","Type 3","forceApp","passive","stripTensile",42,"stripAdhesion",0,"stripFricAngle",41)
當(dāng)GeoTextile 用于加固邊坡時(shí)，材料被放置在一定寬度的條帶中。條帶覆蓋率(Strip Coverage)指的是這些條帶在平面外方向（即沿邊坡）的間距。如果這些條帶是連續(xù)鋪設(shè)的，相鄰條帶之間沒(méi)有空隙，那么條帶覆蓋率=100%。如果條帶不是連續(xù)鋪設(shè)的（即相鄰條帶之間有空隙），那么條帶覆蓋率將低于100%。例如，如果鋪設(shè)4米寬的條帶，每條帶之間有2米的間距，那么條帶覆蓋率將等于67%(即4/(4+2))。
接下來(lái)添加Geotexile的布置方式，使用Support>Add Support Pattern分別設(shè)置三類支護(hù),如下圖所示。
addsupport("pattern","id",1,"matid",1,"orientation","anglefromhoriz","angle",0,"length",9,"spaced","along","dist",0.6,"frompoint",0,0.25,"topoint",0,3.9)addsupport("pattern","id",2,"matid",2,"orientation","anglefromhoriz","angle",0,"length",9,"spaced","along","dist",0.6,"frompoint",0,4.45,"topoint",0,6.5)addsupport("pattern","id",3,"matid",3,"orientation","anglefromhoriz","angle",0,"length",9,"spaced","along","dist",0.6,"frompoint",0,6.85,"topoint",0,8.3)
最后一步設(shè)定邊坡限制。
definelimits("limit",-14,-1,"limit2",2,19.5)
每種方法計(jì)算的最小安全系數(shù)為:
Bishop Simplified Method: fos=1.459
GLE/M-P Method: fos=1.459
Janbu Simplified Method: fos=1.324
Spencer Method: fos=1.458
4 SLIDE計(jì)算
相同的數(shù)據(jù)在SLIDE下運(yùn)行，每種方法計(jì)算的最小安全系數(shù)為:
Bishop Simplified Method: fos=1.483
GLE/M-P Method: fos=1.484
Janbu Simplified Method: fos=1.380
Spencer Method: fos=1.483
工程師必備
- 項(xiàng)目客服
- 培訓(xùn)客服
- 平臺(tái)客服
TOP
