Improvement of Liujiagou and Shengou Gullies (1) Scale(1) Scale

Liujiagou starts at Xining-Datong Highway and ends at Beichuan River. Gully cross section improvement, gully channel earth backfill and greening are planned for Liujiagou. The section to be improved has a total length of 0.9km, as detailed in Table 2.8-1;

Shengou starts at the flood drainage culvert intersecting with Chaoyangdianqu, and ends at the Beichuan River. The improvement works mainly cover improvement of cross section, slopes and greening along both banks of the gully. The section to be improved is 0.9km in length, as detailed in Table 2.8-1.

Table 2.8-1 Gully Improvement Scale

Gully Location Gully

(2) Activities to Be Conducted for the Improvement

Table 2.8-2 Activities to Be Conducted for Gully Improvement

Liujiagou Shengou

Beichuan River Flood drainage culvert of Chaoyangdianqu to river mouth of Beichuan River

Length of

Improvement 0.9km 0.9km

Scheme Flood discharge canal + slope protection, as shown in Figure 2.8-3 Longitudinal

Section As described in Table 2.8-3

Cross-section Gabion cushion lining structure, as shown in Table 2.8-4

Slope Protection

Reinforced Mike mat fixed with U-shaped nails will be used for slope protection, and anchoring trench will be used on the top of the slope; at the toe of the slope, gabion protection will be added to protect against scouring, with PET geotextile used for filter. The slope ratio is 1:2. One meter wide berms are provided at an interval of 5m. Trapezoidal cross-section drainage ditch of C15 plain concrete with a bottom width of 20cm is provided at the the slope bottom. The cross section dimensions of the drainage ditsch are 0.4×0.3m.

See Figure 2.8-4 for details.

Landscape

greening See Table 2.8-5 for details, effect picture shown in Figure 2.8-5 Sanitation

Facilities Garbage bins are to be provided close to the walkway by the gully at an interval of 100m

9 18 Wastewater

Pipe As shown in Table 2.8-6

Figure 2.8-3 Sketch of Design

Table 2.8-3 Design of Gully Longitudinal Section

Gully Descriptio

n

Section Description and Stake No. (from upper to lower)

Segmental Length (m)

Designed Longitudin al Slope (%)

Liujiagou

Xining-Datong Highway Bridge -Railway

Bridge 443.624 2.25

(0+000-0+443.624)

Railway bridge – Confluence into the

Beichuan River 506.435 1.38

(0+465.948-0+900.000)

Shengou

Chaoyangdianqu flood drainage culvert

~Xining-Datong Highway bridge 264.721 1.63 (0+000.000-0+264.721)

Xining-Datong Highway bridge ~

confluence into the Beichuan River 595.000 1.00 (0+300.000-0+895.000)

Table 2.8-4 Design of Cross Sections for Gully Improvement

Gully

Name Section and Stake No. Dimensions of Cross Section (m) Bottom Depth Canal Depth Slope Ratio Liujiagou Xining-Datong Highway bridge

-railway bridge 6.0 1.8 1：1

railway bridge –confluence into

Figure 2.8-4 Typical Cross-section of Slope Protection Table 2.8-5 Plan of Landscape Greening

Types of Armeniaca vulgaris Lam. var. ansu (Maxim.), Amorpha fruticosa., Sabina vulgaris, Rosa xanthina, lilac, forsythia, Lycium chinense Miller, Zizyphus jujuba mill, Polygonum aubertii L.Henry, Lonicera tragophylla, Clematis, Coronilla varia, Iris lactea var. chinensis, Hemerocallis fulva, Rudbeckia hirta, Nephrolepis auriculata etc

Greening considered but also the requirements of the bank shore landscape.

Therefore, willow, popular in Xining region with good shape, is taken as the main street tree. And meanwhile, such main landscape trees in Xining region as poplar and birch are interplanted. Such interplantation will not only mitigate the visual fatigue of people during driving and walking but also can effectively avoid diseases due to large area singular plantation of plants

recreationa various bushed with flowers or leaves of various colors underneath the trees, adopt locally bright-colored bushes which will be cut to smooth lively outline, so as to form various circles and spaces, plant seasonal flowers and turf at the lower space, so as to form well-distributed, bright-colored flora with distinct levels by means of

anchoring trench

U-shaped nail, quincunx arranged with an interval of 1m

Geo-textile

Gabion toe protection

Slope coated with Galfan and padded with Mike mat

combination of trees, bushes, flowers and herbs

Fig. 2.8-5 Intentioned Gully Landscape Green Land Design

Table 2.8-6 Design of Wastewater Interception Pipes

Liujiagou Shengou

From Beichuan River to Chaoyangdianqu, with total service area of 43.22ha

Construction of 1.8km of main pipe and 0.2km of branch pipe for waste water collection, and the collected waste water will be about 224m³/d and sent to No.3 WWTP for treatment

Construction Activities

Separate collection of rain water and waste water will be adopted. However, in accordance with gully improvement scheme, the two sides of the gully will be mainly of green land zones, most of the rainfall will seep into the ground. It’s hard to form the surface runoff. Therefore, placement of rain water pipe network is not considered in the gully

improvement. In order to collect the waste water on two sides of the gully, waste water interception pipes are placed on two sides of the gully to help gully improvement.

Layout of Pipes

with consideration of the gully improvement scheme, the drainage plan and the existing drainage pipe network in the area, waste water collection pipes are to be placed in a direction from east to west underneath the green land zone on both sides of Shengou, for collecting the waste water on two sides of the gully and transporting the waste water of Chaoyangdianqu into the existing DN600 waste water Interception pipe on the east bank of the Beichuan River. The collected waste water will finally enter into No.3 WWTP.

Quantities

The main materials and shafts/chambers of Shengou are shown in Table 2.8-7.

120º plain concrete will be used for reinforced concrete pipe, foundation uses C35 concrete. See Table 2.8-8 and Figure 2.8-6 for details.

Table 2.8-7 Summary of Main Materials and Shafts/Chambers of Shengou

No. Description Specific

ation Material Unit Quantity Remarks 1 Reinforced concrete

drainage pipe DN600 Reinforced

concrete m 900

2 Reinforced concrete

drainage pipe DN400 Reinforced

concrete m 900

3 Reinforced concrete

drainage pipe DN300 Reinforced

concrete m 200 Branch

pipe

4 Maintenance shaft Φ1000 brick No. 60

Table 2.8-8 Dimension of Plain Concrete Foundation DN Thickness of Pipe Wall Dimension of Foundation

Slope

a B C1 C2

300 40 80 540 80 95 1:0.75

400 47 100 694 100 123 1:0.75

600 60 100 920 100 180 1:0.75

Figure 2.8 -6 Illustration of Foundation of Pipeline