**7.1. Reconstruction of Retaining Wall (Prague - Horni Pocernice, Czech Republic)**

#### **Task:**

The retaining wall (Figs 16-19) is located at the D11 highway at Prague, Horni Pocernice. The highway runs here in a deep trench with walls reaching to 10 m height. The works during the reconstruction of the retaining wall included:


#### **Solution:**

Technology of pressure grouting was used in order to stabilize soil and fill potential cavities behind the retaining wall. Double component PU resin Geopur® 082/90 was used as a grouting medium. Grouting works were performed through drilled or hammered in perforated steel grouting tubes of 16/22 mm diameter. Drillings were drilled approximately perpendicularly to the wall, to the depth of 2 to 3 m in a periodic grid. In total, an area of the wall of approx. 1500 m2 was stabilized, total of approx. 10 000 m of grouting rods were drilled, and a total of approx. 46900 kg of Geopur® grouting resin was consumed.

**Figure 16.** Original state of the retaining wall

volume weight.

**Republic)** 

works.

**Solution:** 

**Task:** 

probably also result of this.

 The ratio of rock grains to the PU binder, distribution of grains, grain size and the possibility of formation of porous foamed material have significant influence to the values of parameters of physical-mechanical properties of the geocomposite. These factors are always very variable at in situ conditions and depend on the bedding conditions of the rock (local porosity, structure, permeability, moisture and etc.). It is therefore necessary to take into consideration during the laboratory testing mainly the

 Samples of lower volume weight contain greater portion of foamed plastic binder. This results in decrease of velocity of longitudinal ultrasound waves spreading through the

 Greater portion of rock grains (higher volume weight) positively influences the strength of the geocomposite. Compressive and tensile strengths increase with increasing

 Geocomposite deforms within the elastic phase mainly in longitudinal direction, transverse deformations are small. This is indicated also by small values of Poisson's ratio. It is caused probably by high porosity of the binder, which is predominantly elastically deformed in the direction of loading force. High values of tensile strength are

The retaining wall (Figs 16-19) is located at the D11 highway at Prague, Horni Pocernice. The highway runs here in a deep trench with walls reaching to 10 m height. The works

1. stabilization of the fill material behind the current wall by grouting technology from static and safety reasons in order to enable performance of the follow up reconstruction

Technology of pressure grouting was used in order to stabilize soil and fill potential cavities behind the retaining wall. Double component PU resin Geopur® 082/90 was used as a grouting medium. Grouting works were performed through drilled or hammered in perforated steel grouting tubes of 16/22 mm diameter. Drillings were drilled approximately perpendicularly to the wall, to the depth of 2 to 3 m in a periodic grid. In total, an area of the wall of approx. 1500 m2 was stabilized, total of approx. 10 000 m of grouting rods were

2. anchoring of steel concrete pole prefabricates of the newly built retaining wall.

drilled, and a total of approx. 46900 kg of Geopur® grouting resin was consumed.

material and decrease of deformation modulus (higher plasticity).

**7. Examples of practical applications of PU grouting** 

during the reconstruction of the retaining wall included:

**7.1. Reconstruction of Retaining Wall (Prague - Horni Pocernice, Czech** 

parameters of samples of lower volume weight.

**Figure 17.** Anchoring works

**Figure 18.** Situation before final completion of the works

Polyurethane Grouting Technologies 327

Grouting works were launched at 7.00 AM. After preparation of the technical equipment, grouting tubes were pushed in. Pushing in of the 1st tube was followed by immediate start of the grouting works. In total, 9 grouting tubes were made. Grouting was done stepwise. Complete stopping of water seepages was reached at 5 PM. In total, 600 kg of Geopur®

**Figure 21.** Grouting material in the surrounding of the water-gate (photo from the control excavation

After 10 years (in February 2011) the river basin authority decided to check the lifetime of the grouting material and its sealing function. An excavation was made down to the concrete construction of the dam. Grouting material was observed on the contact with the concrete structure and in the surrounding (Fig. 21). The material looked undamaged and fulfilled the sealing purpose. It was solid and dry. The efficiency of the performed PU

**7.3. Elimination of contaminated water outflows from the uranium deposit** 

After stopping of mining at the uranium deposit Rozna in 1996, the mine was flooded. The groundwater from the old exploited areas, rich in uranium, infiltrated into the old investigation boreholes, even though the boreholes were sealed in the past (Fig. 22). Contaminated water threatened a drinking water reservoir, and therefore it was necessary

The problem was successfully eliminated by application of PU grouting using Geopur® grouting system (Fig. 23). The boreholes were sealed with grouting and the outflows of contaminated water stopped. It was proved that using PU resin of Geopur® type with foaming factor of 12 it is possible to efficiently stop seepages through porous geological

**Solution:** 

after 10 years)

**Task:** 

**Solution:** 

pressure grouting was proved.

**(Rozna, Czech Republic)** 

environment or boreholes.

to stop the dangerous outflows from these boreholes.

082/350 PU resin material was used.

**Figure 19.** Detail of finalized anchor

Drilling of the anchors was made in places of openings of the anchored concrete poles (Figs 17, 19). Self drilling R type rock bolts were used. The length of the anchors was 8 to 10 m, according to the particular geological conditions at the place of the installed anchor (always to reach at least 2 m of stiff rock environment). After drilling in of the anchor rods, pressure grouting was performed through the installed anchor (AR32N) using two component PU resin Geopur® 082/600. The length of the grouted anchor root was approx. 3 to 6 m and approx. 50-60 kg of grouting resin was applied into each anchor.

In total 276 anchors were installed of total length of 1896 m. The consumption of grouting resins Geopur® reached approx. 13 200 kg.

#### **7.2. Hatarmenti water-gate (Zagyva River, Hungary)**

#### **Task:**

During the time of catastrophic floods on the Tisza River, which occurred from February to March 2001, intensive water seepages occurred around the Hatarmenti water-gate on the Zagyva River by the town of Szolnok (Fig. 20). The dam contains two concrete units with openings of 120cm×120cm. Intensive seepages threatened the stability of the dam. Insulation by PU pressure grouting, using pushed-in grouting tubes at the water-side of the dam, was proposed.

**Figure 20.** View of the Hatarmenti water-gate

#### **Solution:**

326 Polyurethane

**Task:** 

proposed.

**Figure 19.** Detail of finalized anchor

resins Geopur® reached approx. 13 200 kg.

**Figure 20.** View of the Hatarmenti water-gate

Drilling of the anchors was made in places of openings of the anchored concrete poles (Figs 17, 19). Self drilling R type rock bolts were used. The length of the anchors was 8 to 10 m, according to the particular geological conditions at the place of the installed anchor (always to reach at least 2 m of stiff rock environment). After drilling in of the anchor rods, pressure grouting was performed through the installed anchor (AR32N) using two component PU resin Geopur® 082/600. The length of the grouted anchor root was approx. 3 to 6 m and

In total 276 anchors were installed of total length of 1896 m. The consumption of grouting

During the time of catastrophic floods on the Tisza River, which occurred from February to March 2001, intensive water seepages occurred around the Hatarmenti water-gate on the Zagyva River by the town of Szolnok (Fig. 20). The dam contains two concrete units with openings of 120cm×120cm. Intensive seepages threatened the stability of the dam. Insulation by PU pressure grouting, using pushed-in grouting tubes at the water-side of the dam, was

approx. 50-60 kg of grouting resin was applied into each anchor.

**7.2. Hatarmenti water-gate (Zagyva River, Hungary)** 

Grouting works were launched at 7.00 AM. After preparation of the technical equipment, grouting tubes were pushed in. Pushing in of the 1st tube was followed by immediate start of the grouting works. In total, 9 grouting tubes were made. Grouting was done stepwise. Complete stopping of water seepages was reached at 5 PM. In total, 600 kg of Geopur® 082/350 PU resin material was used.

**Figure 21.** Grouting material in the surrounding of the water-gate (photo from the control excavation after 10 years)

After 10 years (in February 2011) the river basin authority decided to check the lifetime of the grouting material and its sealing function. An excavation was made down to the concrete construction of the dam. Grouting material was observed on the contact with the concrete structure and in the surrounding (Fig. 21). The material looked undamaged and fulfilled the sealing purpose. It was solid and dry. The efficiency of the performed PU pressure grouting was proved.
